Aluminum-lithium alloys, and methods for producing the same

ABSTRACT

New Al—Li alloy bodies and methods of producing the same are disclosed. The new Al—Li alloy bodies may be produced by preparing the aluminum alloy body for post-solutionizing cold work, cold working by at least 25%, and then thermally treating. The new Al—Li alloy bodies may realize improved strength and other properties.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application is a continuation of International PatentApplication No. PCT/US2013/027858, filed Feb. 27, 2013, which claimspriority to U.S. Provisional Patent Application No. 61/608,075, filedMar. 7, 2012, entitled, “IMPROVED ALUMINUM-LITHIUM ALLOYS, AND METHODSFOR PRODUCING THE SAME”, which are both incorporated herein by referencein their entirety.

This patent application is related to (a) U.S. Provisional PatentApplication No. 61/608,050, filed Mar. 7, 2012, and (b) U.S. ProvisionalPatent Application No. 61/608,034, filed Mar. 7, 2012, and (c) U.S.Provisional Patent Application No. 61/608,092, filed Mar. 7, 2012, and(d) U.S. Provisional Patent Application No. 61/608,098, filed Mar. 7,2012.

BACKGROUND

Aluminum alloys are useful in a variety of applications. However,improving one property of an aluminum alloy without degrading anotherproperty is elusive. For example, it is difficult to increase thestrength of an alloy without decreasing the toughness of an alloy. Otherproperties of interest for aluminum alloys include corrosion resistanceand fatigue crack growth resistance, to name two.

SUMMARY OF THE DISCLOSURE

Broadly, the present patent application relates to improved wrought,heat treatable aluminum alloys, and methods for producing the same.Specifically, the present patent application relates to improvedwrought, Al—Li alloy products, and methods for producing the same.Generally, the Al—Li alloy products achieve an improved combination ofproperties due to, for example, the post-solutionizing cold work andpost-cold working thermal treatments, as described in further detailbelow. For purposes of the present application, “Al—Li alloys” arealuminum alloys containing 0.25-5.0 wt. % lithium.

One conventional process for producing Al—Li alloy products in rolledform is illustrated in FIG. 1. In the conventional process, an Al—Lialloy body is cast (10), after which it is homogenized (11) and then hotrolled to an intermediate gauge (12). Next, the Al—Li alloy body is coldrolled (13) to final gauge, after which it is solution heat treated andquenched (14). “Solution heat treating and quenching” and the like,generally referred to herein as “solutionizing”, means heating analuminum alloy body to a suitable temperature, generally above thesolvus temperature, holding at that temperature long enough to allowsoluble elements to enter into solid solution, and cooling rapidlyenough to hold the elements in solid solution. The solid solution formedat high temperature may be retained in a supersaturated state by coolingwith sufficient rapidity to restrict the precipitation of the soluteatoms as coarse, incoherent particles. After solutionizing (14), theAl—Li alloy body may be optionally stretched a small amount (e.g., 1-5%)for flatness (15), thermally treated (16) and optionally subjected tofinal treatment practices (17). FIG. 1 is consistent with a process pathfor producing aluminum alloys in a T6 temper (the T6 temper is definedlater in this patent application).

One embodiment of a new process for producing new Al—Li alloy productsis illustrated in FIG. 2. In this new process, an Al—Li alloy body isprepared for post-solutionizing cold work (100), after which it is coldworked (200), and then thermally treated (300). The new process may alsoinclude optional final treatment(s) (400), as described in furtherdetail below. “Post-solutionizing cold work” and the like means coldworking of an aluminum alloy body after solutionizing. The amount ofpost-solutionizing cold work applied to the Al—Li alloy body isgenerally at least 25%, such as more than 50% cold work. By firstsolutionizing, and then cold working by at least 25%, and thenappropriately thermally treating the Al—Li alloy body, the Al—Li alloybody may realize improved properties, as described in further detailbelow. For example, strength increases of 5-40%, or more, may berealized relative to conventional aluminum alloy products in the T6and/or T87 temper, and in a fraction of the time required to processthose conventional aluminum alloy products to the T6 and/or T87 temper(e.g., 10%-90% faster than T6 and/or T87 temper processed alloys). Thenew Al—Li alloy body may also realize good ductility, generallyrealizing an elongation of more than 4%, such as elongations of 6-16%,or higher. The new aluminum alloy body may realize such strengthimprovements with no loss in fracture toughness. In some instances, thenew Al—Li alloy body realizes improved fracture toughness, such as 5-25%better fracture toughness than conventional aluminum alloy products inthe T6 and/or T87 temper. Other properties may also be maintained and/orim

A. Preparing for Post-Solutionizing Cold Work

As illustrated in FIG. 2, the new process includes preparing an aluminumalloy body for post-solutionizing cold work (100). The aluminum alloybody may be prepared for post-solutionizing cold work (100) in a varietyof manners, including the use of conventional semi-continuous castingmethods (e.g., direct chill casting of ingot) and continuous castingmethods (e.g., twin-roll casting). As illustrated in FIG. 3, thepreparing step (100) generally comprises placing the aluminum alloy bodyin a form suitable for the cold working (120) and solutionizing thealuminum alloy body (140). The placing step (120) and solutionizing step(140) may occur sequentially or concomitant to one another. Somenon-limiting examples of various preparing steps (100) are illustratedin FIGS. 4-8, which are described in further detail below. Other methodsof preparing an aluminum alloy body for post-solutionizing cold work(100) are known to those skilled in the art, and these other methods arealso within the scope of the preparing step (100), even though notexplicitly described herein.

In one approach, the preparing step (100) comprises a semi-continuouscasting method. In one embodiment, and with reference now to FIG. 4, theplacing step (120) includes casting the aluminum alloy body (122) (e.g.,in the form of an ingot or billet), homogenizing the aluminum alloy body(124), hot working the aluminum alloy body (126), and optionally coldworking the aluminum alloy body (128). After the placing step (120), thesolutionizing step (140) is completed. Similar steps may be completedusing continuous casting operations, although the aluminum alloy bodywould not be in the form of an ingot/billet after casting (120).

In another embodiment, and with reference now to FIG. 5, a preparingstep (100) includes casting the aluminum alloy body (122), homogenizingthe aluminum alloy body (124) and hot working the aluminum alloy body(126). In this embodiment, the hot working step (126) may be completedto place soluble elements in solid solution, after which the aluminumalloy body is quenched (not illustrated), thereby resulting in thesolutionizing step (140). This is one example of the placing step (120)and solutionizing step (140) being completed concomitant to one another.This embodiment may be applicable to press-quenched products (e.g.,extrusions) and hot rolled products that are quenched after hot rolling,among others.

In another approach, the preparing step (100) comprises a continuouscasting method, such as belt casting, rod casting, twin roll casting,twin belt casting (e.g., Hazelett casting), drag casting, and blockcasting, among others. One embodiment of a preparing step (100)employing a continuous casting methodology is illustrated in FIG. 6 a.In this embodiment, the aluminum alloy body is cast and solutionized atabout the same time (142), i.e., concomitant to one another. The castingplaces the aluminum alloy body in a form sufficient to cold work. Whenthe solidification rate during casting is sufficiently rapid, thealuminum alloy body is also solutionized. In this embodiment, thecasting/solutionizing step (142) may include quenching of the aluminumalloy body after casting (not illustrated). This embodiment may beapplicable to twin-roll casting processes, among other castingprocesses. Some twin-roll casting apparatus and processes capable ofcompleting the process of FIG. 6 a are described in U.S. Pat. No.7,182,825, U.S. Pat. No. 7,125,612, U.S. Pat. No. 7,503,378, and U.S.Pat. No. 6,672,368, and are described relative to FIGS. 6 b-1 through 6x, below.

In another embodiment, and with reference now to FIG. 7, a preparingstep (100) includes casting the aluminum alloy body (122) and, after thecasting step (122), then solutionizing the aluminum alloy body (140). Inthis embodiment, the placing step (120) comprises the casting (122).This embodiment is applicable to twin-roll casting processes, amongother casting processes.

In another embodiment, and with reference now to FIG. 8, a preparingstep (100) includes casting the aluminum alloy body (122), hot workingthe aluminum alloy body (126), and optionally cold working the aluminumalloy body (128). In this embodiment, the placing step (120) includesthe casting (122), the hot working (126), and optional cold working(128) steps. After the placing step (120), the solutionizing step (140)is completed. This embodiment may be applicable to continuous castingprocesses.

Many of the steps illustrated in FIGS. 2 a, 3-6 a and 7-8 can becompleted in batch or continuous modes. In one example, the cold working(200) and thermal treatment step (300) are completed continuously. Inthis example, a solutionized aluminum alloy body may enter the coldworking operation at ambient conditions. Given the relatively shortthermal treatment times achievable with the new processes describedherein, the cold worked aluminum alloy body could be immediatelythermally treated (300) after cold working (e.g., in-line) (e.g., thethermally treating step (300) is completed concomitant to the coldworking step (200)). Conceivably, such thermal treatments could occurproximal the outlet of the cold working apparatus, or in a separateheating apparatus connected to the cold working apparatus. This couldincrease productivity. In another example, and as described in the ColdWorking section (Section B), below, the preparing step (100) and coldworking step (200) are completed continuously (e.g., when a continuouslycasting apparatus is used, and such that the continuously as-castaluminum alloy body may immediately and continuously proceed to the coldworking step (200), such as shown in FIG. 6 a. In this embodiment, thecasting/solutionizing step (142) may include quenching the aluminumalloy body to a suitable cold working temperature (e.g., less than 150°F.). In another embodiment, all three of the preparing step (100), thecold working step (200) and the thermal treatment step (300) arecompleted continuously.

As described above, the preparing step (100) generally comprisessolutionizing of the aluminum alloy body. As noted above,“solutionizing” includes quenching (not illustrated) of the aluminumalloy body, which quenching may be accomplished via a liquid (e.g., viaan aqueous or organic solution), a gas (e.g., air cooling), or even asolid (e.g., cooled solids on one or more sides of the aluminum alloybody). In one embodiment, the quenching step includes contacting thealuminum alloy body with a liquid or a gas. In some of theseembodiments, the quenching occurs in the absence of hot working and/orcold working of the aluminum alloy body. For example, the quenching mayoccur by immersion, spraying and/or jet drying, among other techniques,and in the absence of deformation of the aluminum alloy body. As shownin the FIGS. 2 a, 3-6 a, 7-9, and 12, the solutionizing step isgenerally the last step of the preparing step and immediately precedesthe cold working step.

Those skilled in the art recognize that other preparing steps (100) canbe used to prepare an aluminum alloy body for post-solutionizing coldwork (e.g., powder metallurgy methods), and that such other preparingsteps fall within the scope of the preparing step (100) so long as theyplace the aluminum alloy body in a form suitable for cold working (120)and solutionize the aluminum alloy body (140), and irrespective ofwhether these placing (120) and solutionizing (140) steps occurconcomitantly (e.g., contemporaneously) or sequentially, andirrespective of whether the placing step (120) occurs before thesolutionizing step (140), or vice-versa.

i. Continuous Casting Embodiments a. Twin-Roll ContinuousCasting—Continuous Casting and Solutionizing

In one embodiment, the aluminum alloy bodies of the present disclosuremay be prepared for post-solutionizing cold work by being continuouslycast between a horizontal two-roll or two-belt caster, wherein thesolutionizing occurs concomitant to the continuous casting (e.g., due tothe continuous casting methodology). In such embodiments, the aluminumalloy bodies may be continuously cast by being juxtaposed and incommunication with a pair of internally cooled rolls. Referring to nowto FIGS. 6 b-1 to 6 b-2, one embodiment of a horizontal twin-rollcontinuous casting apparatus is illustrated. This apparatus uses a pairof counter-rotating cooled rolls R₁ and R₂ rotating in the directions ofthe arrows A₁ and A₁, respectively. The term horizontal means that thecast strip (S) is produced in a horizontal orientation or at an angle ofplus or minus 30 degrees from horizontal. As shown in more detail inFIG. 6 b-2, a feed tip T, which may be made from a ceramic material, maydistribute molten metal M in the direction of the arrow. Gaps G₁ and G₂between the feed tip T and the respective rolls R₁ and R₂ may bemaintained as small as possible; however, contact between the tip T andthe rolls R₁ and R₂ should be avoided. Without wishing to be bound bythe theory, it is believed that maintaining small gaps aids to preventmolten metal from leaking out and to minimize the exposure of the moltenmetal to the atmosphere along the R₁ and R₂. A suitable dimension of thegaps G₁ and G₂ may be 0.01 inch (0.254 mm). A plane L through thecenterline of the rolls R₁ and R₂ passes through a region of minimumclearance between the rolls R₁ and R₂ referred to as the roll nip N.

The molten metal M may directly contact the cooled rolls R₁ and R₂ atregions 2-6 and 4-6, respectively. Upon contact with the rolls R₁ andR₂, the metal M begins to cool and solidify. The cooling metal producesan upper shell 6-6 of solidified metal adjacent the roll R₁ and a lowershell 8-6 of solidified metal adjacent to the roll R₂. The thickness ofthe shells 6-6 and 8-6 increases as the metal M advances towards the nipN. Large dendrites 10-6 of solidified metal (not shown to scale) may beproduced at the interfaces between each of the upper and lower shells6-6 and 8-6 and the molten metal M. The large dendrites 10-6 may bebroken and dragged into a center portion 12-6 of the slower moving flowof the molten metal M and may be carried in the direction of arrows C₁and C₂. The dragging action of the flow can cause the large dendrites10-6 to be broken further into smaller dendrites 14-6 (not shown toscale). In the central portion 12-6 upstream of the nip N referred to asa region 16-6, the metal M is semi-solid and may include a solidcomponent (the solidified small dendrites 14-6) and a molten metalcomponent. The metal M in the region 16-6 may have a mushy consistencydue in part to the dispersion of the small dendrites 14-6 therein. Atthe location of the nip N, some of the molten metal may be squeezedbackwards in a direction opposite to the arrows C₁ and C₂. The forwardrotation of the rolls R₁ and R₂ at the nip N advances substantially onlythe solid portion of the metal (the upper and lower shells 6-6 and 8-6and the small dendrites 14-6 in the central portion 12-6) while forcingmolten metal in the central portion 12-6 upstream from the nip N suchthat the metal may be completely solid as it leaves the point of the nipN. Downstream of the nip N, the central portion 12-6 may be a solidcentral layer, or region, 18-6 containing the small dendrites 14-6sandwiched between the upper shell 6-6 and the lower shell 8-6. In thecentral layer, or region, 18-6, the small dendrites 14-6 may be 20microns to 50 microns in size and have a generally globular shape. Thethree layers, or regions of a single cast metal sheet/layer, of theupper and lower shells 6-6 and 8-6 and the solidified central layer 18-6constitute a solid cast strip 20-6. Thus, the aluminum alloy strip 20-6includes a first layer, or region, of an aluminum alloy and a secondlayer, or region, of the aluminum alloy (corresponding to the shells 6-6and 8-6) with an intermediate layer, or region, (the solidified centrallayer 18-6) therebetween. The solid central layer, or region, 18-6 mayconstitute 20 percent to 30 percent of the total thickness of the strip20-6. The concentration of the small dendrites 14-6 may be higher in thesolid central layer 18-6 of the strip 20-6 than in the semi-solid region16-6 of the flow, or the central portion 12-6. The molten aluminum alloymay have an initial concentration of alloying elements includingperitectic forming alloying elements and eutectic forming alloyingelements, such as any of the alloying elements described in theComposition section (Section G), below. Examples of alloying elementsthat are peritectic formers with aluminum include Ti, V, Zr and Cr.Examples of eutectic formers with aluminum include Si, Fe, Ni, Zn, Mg,Cu, Li and Mn.

As noted above, the aluminum alloy body includes 0.5-5.0 wt. % lithium.During solidification of an aluminum alloy melt, dendrites typicallyhave a lower concentration of eutectic formers than the surroundingmother melt and higher concentration of peritectic formers. In theregion 16-6, in the center region upstream of the nip, the smalldendrites 14-6 are thus partially depleted of eutectic formers while themolten metal surrounding the small dendrites is somewhat enriched ineutectic formers. Consequently, the solid central layer, or region, 18-6of the strip 20-6, which contains a large population of dendrites, isdepleted of eutectic formers and is enriched in peritectic formers incomparison to the concentration of the eutectic formers and theperitectic formers in the upper shell 6-6 and the lower shell 8-6. Inother words, the concentration of eutectic forming alloying elements inthe central layer, or region, 18-6 is generally less than in the firstlayer, or region, 6-6 and second layer, or region, 8-6. Similarly, theconcentration of peritectic forming alloying elements in the centrallayer, or region, 18-6 is generally greater than in the first layer, orregion, 6-6 and second layer, or region, 8-6. Thus, in some embodiments,an alloy comprises a larger amount (higher average through thicknessconcentration in that region) of lithium in the upper region or lowerregion of the alloy product as compared to the amount of lithium at thecenterline of the aluminum alloy product, wherein the concentration inthese regions is determined using the Concentration Profile Procedure,described below. In one embodiment, an alloy comprises a higherconcentration of Li in both the upper region and the lower region of thealloy product. In one embodiment, the alloy comprises at least a 1%higher Li concentration (average concentration in the upper or lowerregion, as applicable) relative to the Li concentration at thecenterline of the product. In one embodiment, the alloy comprises atleast a 3% higher Li concentration (average concentration in the upperor lower region, as applicable) relative to Li concentration at thecenterline of the product. In one embodiment, the alloy comprises atleast a 5% higher Li concentration (average concentration in the upperor lower region, as applicable) relative to the Li concentration at thecenterline of the product. In one embodiment, the alloy comprises atleast a 7% higher Li concentration (average concentration in the upperor lower region, as applicable) relative to the Li concentration at thecenterline of the product. In one embodiment, the alloy comprises atleast a 9% higher Li concentration (average concentration in the upperor lower region, as applicable) relative to the Li concentration at thecenterline of the product.

Concentration Profile Procedure—for Si, Mg, Cu, Zn, Mn, and Fe

1. Sample Preparation

-   -   Aluminum sheet samples are mounted in Lucite and the        longitudinal surface is polished using the standard        metallographic preparation procedure (ref: ASTM E3-01 (2007)        Standard Guide for Preparation of Metallographic Specimens). The        polished surface of the samples is coated with carbon using        commercially available carbon coating equipment. The carbon        coating is a few microns thick.

2. Electron Probe Micro Analysis (EPMA) Equipment

-   -   A JEOL JXA8600 Superprobe is used to obtain through-thickness        composition profiles in the prepared aluminum sheet samples. The        Superprobe has four Wave Dispersive Spectrometer (WDS)        detectors, two of which are gas flow (P-10) counters, and the        others being Xe-gas sealed counters. The detection range of        elements is from Beryllium (Be) to Uranium (U). The quantitative        analysis detection limit is 0.02 wt %. The instrument is        equipped with Geller Microanalytical Dspec/Dquant automation        which allows stage control and unattended quantitative and        qualitative analysis.

3. Electron Probe Micro Analysis (EPMA) Analysis Procedure

-   -   The Superprobe is set to the following conditions: accelerating        voltage 15 kV, beam intensity 100 nA, defocus electron beam to        an appropriate size such that a minimum of 13 different sections        of the sample can be measured (e.g., defocused to 100 μm for a        0.060 inch thick specimen), and exposure time for each element        is 10 seconds. Background correction was done for the sample        surface at three random locations with a counting time of 5        seconds on positive and negative backgrounds.    -   One EPMA linescan is defined as scanning the whole thickness of        the sheet samples at multiple locations along a straight line        perpendicular to the rolling direction of the sample. An odd        number of spots are used, with the mid-number spots at the        center line of the sheet sample. The spacing between the spots        is equivalent to the beam diameter. At each spot, any of the        following elements may be analyzed, as appropriate: Mn, Cu, Mg,        Zn, Si, and Fe. Si is analyzed by a PET diffracting crystal with        a gas flow (P-10) counter; Fe, Cu, Zn, and Mn are by a LIF        diffracting crystal with a Xe-gas sealed counter; Mg is analyzed        by a TAP diffracting crystal with a gas flow (P-10) counter. The        counting time for each element is 10 seconds. This linescan is        repeated 30 times down the length of the sheet sample. At any        one location of the sample, the reported composition of each        element should be the averaged value of 30 measurements at the        same thickness locations    -   The concentration in the upper and lower regions is the average        measured concentration in each of these regions, excluding (i)        the edge (surface) of the upper region and the lower region        and (ii) the transition zone between the center region and each        of the upper region and the lower region. The concentration of        an element must be measured at a minimum of four (4) different        locations in each of the upper and lower regions to determine        the average concentration of such element in each of those        regions.    -   Elements measured were calibrated using the DQuant analysis        package CITZAF, v4.01 with ZAF/Phi(pz) correction model        Heinrich/Duncumb-Reed. This technique comes from Dr. Curt        Heinrich of NIST, using a traditional Duncumb-Reed absorption        correction. (see, Heinrich, Microbeam Analysis—1985, 79;—1989,        223)

Concentration Profile Procedure—for Li (Serial Sectioning)

-   -   For products containing lithium, serial sectioning is used        wherein a section (through thickness) is obtained by (i)        machining for samples having a thickness of 0.030 or higher,        or (ii) chemical thinning via an appropriate chemical etchant        for samples having a thickness of less than 0.030. At least 13        different through thickness samples are obtained and such that a        centerline sample is always produced. Each of samples is then        analyzed for its Li content by atomic absorption.

The rolls R₁ and R₂ may serve as heat sinks for the heat of the moltenmetal M. In one embodiment, heat may be transferred from the moltenmetal M to the rolls R₁ and R₂ in a uniform manner to ensure uniformityin the surface of the cast strip 20-6. Surfaces D₁ and D₂ of therespective rolls R₁ and R₂ may be made from steel or copper and may betextured and may include surface irregularities (not shown) which maycontact the molten metal M. The surface irregularities may serve toincrease the heat transfer from the surfaces D₁ and D₂ and, by imposinga controlled degree of non-uniformity in the surfaces D₁ and D₂, resultin uniform heat transfer across the surfaces D₁ and D₂. The surfaceirregularities may be in the form of grooves, dimples, knurls or otherstructures and may be spaced apart in a regular pattern of 20 to 120surface irregularities per inch, or about 60 irregularities per inch.The surface irregularities may have a height ranging from 5 microns to50 microns, or alternatively about 30 microns. The rolls R₁ and R₂ maybe coated with a material to enhance separation of the cast strip fromthe rolls R₁ and R₂ such as chromium or nickel.

The control, maintenance and selection of the appropriate speed of therolls R₁ and R₂ may impact the ability to continuously cast strips usingthe present apparatus and methods. The roll speed determines the speedthat the molten metal M advances towards the nip N. If the speed is tooslow, the large dendrites 10-6 will not experience sufficient forces tobecome entrained in the central portion 12-6 and break into the smalldendrites 14-6. In an embodiment, the roll speed may be selected suchthat a freeze front, or point of complete solidification, of the moltenmetal M may form at the nip N. Accordingly, the present castingapparatus and methods may be suited for operation at high speeds such asthose ranging from 25 to 400 feet per minute; alternatively from 50 to400 feet per minute; alternatively from 100 to 400 feet per minute; andalternatively from 150 to 300 feet per minute. The linear rate per unitarea that molten aluminum is delivered to the rolls R₁ and R₂ may beless than the speed of the rolls R₁ and R₂ or about one quarter of theroll speed. High-speed continuous casting may be achievable with thepresently disclosed apparatus and methods, at least in part, because thetextured surfaces D₁ and D₂ ensure uniform heat transfer from the moltenmetal M. Due to such high casting speeds and associated rapidsolidification rates, the soluble constituents may be substantiallyretained in solid solution, i.e., the solutionizing step may occurconcomitant to the casting step.

The roll separating force may be a parameter in using the presentlydisclosed casting apparatus and methods. One benefit of the presentlydisclosed continuous casting apparatus and methods may be that solidstrip is not produced until the metal reaches the nip N. The thicknessis determined by the dimension of the nip N between the rolls R₁ and R₂.The roll separating force may be sufficiently great to squeeze moltenmetal upstream and away from the nip N. Excessive molten metal passingthrough the nip N may cause the layers of the upper and lower shells 6-6and 8-6 and the solid central region 18-6 to fall away from each otherand become misaligned. Insufficient molten metal reaching the nip N maycause the strip to form prematurely. A prematurely formed strip may bedeformed by the rolls R₁ and R₂ and experience centerline segregation.Suitable roll separating forces may range from 25 to 300 pounds per inchof width cast, or 100 pounds per inch of width cast. In general, slowercasting speeds may be needed when casting thicker gauge strips in orderto remove the heat. Such slower casting speeds do not result inexcessive roll separating forces because fully solid aluminum strip isnot produced upstream of the nip. The grains in the aluminum alloy strip20-6 are substantially undeformed because the force applied by the rollsis low (300 pounds per inch of width or less). Furthermore, since thestrip 20-6 is not solid until it reaches the nip N; it will not be “hotrolled”. Thus, the strip 20-6 does not receive a thermo-mechanicaltreatment due to the casting process itself, and when not subsequentlyhot rolled, the grains in the strip 20-6 will generally be substantiallyundeformed, retaining their initial structure achieved uponsolidification, i.e. an equiaxial structure, such as globular, prior tothe cold working step (200).

Thin gauge aluminum strip products may be cast using the presentlydescribed continuously casting apparatus and methods. Aluminum alloystrips may be produced at thicknesses of 0.100 inch or less at castingspeeds ranging from 25 to 400 feet per minute; alternatively from 50 to400 feet per minute; and alternatively from 100 to 400 feet per minute.Thicker gauge aluminum alloy strips may also be produced using thepresently disclosed methods, for example at a thickness of 0.249 inch,or less. Thus, the continuously cast strips generally have a thicknessof a sheet or foil product, per aluminum association standards.

The roll surfaces D₁ and D₂ may heat up during casting and are may beprone to oxidation at elevated temperatures. Non-uniform oxidation ofthe roll surfaces during casting can change the heat transfer propertiesof the rolls R₁ and R₂. Hence, the roll surfaces D₁ and D₂ may beoxidized prior to use to minimize changes thereof during casting. It maybe beneficial to brush the roll surfaces D₁ and D₂ from time-to-time, orcontinuously, to remove debris which may build up during casting ofaluminum and aluminum alloys. Small pieces of the cast strip may breakfree from the strip S and adhere to the roll surfaces D₁ and D₂. Thesesmall pieces of aluminum alloy strip may be prone to oxidation, whichmay result in non-uniformity in the heat transfer properties of the rollsurfaces D₁ and D₂. Brushing of the roll surfaces D₁ and D₂ avoids thenon-uniformity problems from debris which may collect on the rollsurfaces D₁ and D₂.

Continuous casting of aluminum alloys according to the presentdisclosure may be achieved by initially selecting the desired dimensionof the nip N corresponding to the desired gauge of the strip S. Thespeed of the rolls R₁ and R₂ may be increased to a desired productionrate or to a speed which is less than the speed which causes the rollseparating force increases to a level which indicates that rolling isoccurring between the rolls R₁ and R₂. Casting at the rates contemplatedby the present invention (i.e. 25 to 400 feet per minute) solidifies thealuminum alloy strip about 1000 times faster than aluminum alloy cast asan ingot cast and improves the properties of the strip over aluminumalloys cast as an ingot. The rate at which the molten metal is cooledmay be selected to achieve rapid solidification of the outer regions ofthe metal. Indeed, the cooling of the outer regions of metal may occurat a rate of at least 1000 degrees centigrade per second.

As mentioned above, due to high casting speeds and associated rapidsolidification rates, soluble constituents may be substantially retainedin solid solution, i.e., the solutionizing step may occur concomitant tothe casting step. The amount of solute retained in solid solution isrelated to an electrical conductivity of an alloy, with lower electricalconductivity values translated to more solute in solid solution. Thus,in one embodiment, an aluminum alloy body made by the continuous castingprocesses disclosed above may realize low electrical conductivityvalues. In one embodiment, due to the concomitant casting andsolutionizing, an aluminum alloy processed according to such methods iswithin 50% of the theoretical minimum electrical conductivity of thealloy. As used in this subsection ((A)(i)), when an aluminum alloy bodyis “within XX % of the theoretical minimum electrical conductivity ofthe alloy”, the alloy has a measured electrical conductivity that placesthe aluminum alloy body with XX % of the difference between the maximumtheoretical electrical conductivity and minimum theoretical electricalconductivity”. In other words, “within XX % of the theoretical minimumelectrical conductivity=((MeasuredEC minusMinimumTheoreticalEC)/(MaximumTheoreticalEC minusMinimumTheoreticalEC)*100%, wherein the measured electrical conductivityis measured after the preparing (100), cold working (200) and thermallytreating (300) steps have been completed, and in accordance with ASTME1004 (2009). For example, if an aluminum alloy has a minimumtheoretical conductivity of 23.7% IACS and has a maximum theoreticalconductivity of 55.3% IACS, the difference between the maximum andminimum theoretical values would be 31.6% IACS. If the actual measuredelectrical conductivity of this same aluminum alloy was 27.7% IACS, itwould be within about 12.7% of the minimum theoretical value(12.6582%=(MeasuredEC minus MinimumTheoreticalEC) divided by(MaximumTheoreticalEC minus MinimumTheoreticalEC), or((27.7−23.7)/31.6). Values for minimum and maximum resistivity may becalculated using the constants provided in Aluminum: Properties andPhysical Metallurgy, ed. J. E. Hatch, American Society for Metals,Metals Park, Ohio, 1984, p. 205, which describe the effects of variouselements in and out of solution on resistivity. Values for resistivitymay then be converted to values for electrical conductivity in % IACS(assumes a base resistivity of pure aluminum of 2.65 micro-ohm-cm). Thetheoretical minimum electrical conductivity relates to a situation whereall alloying elements are in solid solution. The theoretical maximumelectrical conductivity relates to a situation where all alloyingelements are out of solid solution.

In one embodiment, an aluminum alloy body made by the continuous castingprocesses disclosed above is within 40% of the theoretical minimumelectrical conductivity of the alloy. In another embodiment, an aluminumalloy processed according to such methods is within 30% of thetheoretical minimum electrical conductivity of the alloy. In yet anotherembodiment, an aluminum alloy processed according to such methods iswithin 20% of the theoretical minimum electrical conductivity of thealloy. In another embodiment, an aluminum alloy processed according tosuch methods is within 15% of the theoretical minimum electricalconductivity of the alloy, or less. Similar electrical conductivityvalues may be realized in the continuous casting embodiments describedbelow in subsections (C) and (D).

b. Example of Continuously Casting with Solutionizing

Molten aluminum alloys having alloying elements present in thepercentage by weight indicated in the below table were continuously caston a heat sink belt caster where the upper belt did not contact thesolidifying metal downstream of the nip. The tests reported herein werenot performed on a roll caster. However, the processes were designed tosimulate casting onto a pair of rolls without working the solidifiedmetal.

Alloy Alloying elements (% by weight) 6-1 0.6 Si—1.4 Fe—1.7 Ni—0.6 Zn6-2 0.9 Mg—0.9 Mn—0.5 Cu—0.45 Fe—0.3 Si 6-3 1.4 Mg—0.25 Mn—0.15 Cu—0.30Fe—0.4 Si

The force per unit width applied to Alloys 6-1 and 6-2 versus the rollspeed for various gap settings is shown graphically in FIGS. 6 c and 6d, respectively. In all instances, the force applied by the rolls wasless than 200 lbs/inch of width.

A strip of Alloy 6-1 (0.09 inch thick) was analyzed for segregation ofalloying elements. The concentration of alloying elements through thethickness of the strip is presented graphically FIG. 6 e for eutecticforming elements (Si, Fe, Ni and Zn) and in FIG. 6 f for peritecticforming elements (Ti, V and Zr). The eutectic forming alloying elementsare partially depleted in the central portion of the strip while theperitectic forming alloying elements are enriched in the central portionof the strip.

FIG. 6 g is a photomicrograph at 25 times magnification of a transversesection through a stack of three strips of Alloy 6-1 produced at acasting speed of 188 feet per minute, mean strip thickness of 0.094inch, strip width of 15.5 inches, and applied force of 103 pounds perinch of width. The full thickness of one strip is seen in FIG. 6 gbetween a pair of thin, dark bands. The central, darker band in the fullstrip corresponds to the central layer 18-6 described above which ispartially depleted of eutectic forming alloying elements while theouter, lighter portions of the fall strip correspond to the upper andlower shells 6-6 and 8-6, described above. FIG. 6 h is a photomicrographof the central strip of FIG. 6 g at 100 times magnification. Theglobular nature of the grains in the central, darker band indicates noworking of the strip occurred in the caster.

FIG. 6 i is a photomicrograph at 25 times magnification of a transversesection through a stack of two strips of Alloy 6-2 produced at a castingspeed of 231 feet per minute, roll gap of 0.0925 inch, strip width of15.5 inches and applied force of 97 pounds per inch of width. The fullthickness of one strip and a portion of the other strip are illustratedby FIG. 6 i. The strip of FIG. 6 i also exhibits a central, darker banddepleted of eutectic forming alloying elements. FIG. 6 j is aphotomicrograph of the center portion of the strip of FIG. 6 i at 100times magnification. The globular nature of the grains in the central,darker band also indicates no working of the strip occurred in thecaster.

A strip of Alloy 6-2 (0.1 inch thick) was analyzed for segregation ofalloying elements. The concentration of alloying elements through thethickness of the strip is presented graphically in FIG. 6 k for eutecticforming elements (Mg, Mn, Cu, Fe and Si) and in FIG. 6 l for peritecticforming elements (Ti and V). The eutectic forming alloying elements arepartially depleted in the central portion of the strip while theperitectic forming alloying elements are enriched in the central portionof the strip.

FIG. 6 m is a photomicrograph at 50 times magnification of a transversesection through an anodized strip of Alloy 6-3 produced at a castingspeed of 196 feet per minute, mean strip thickness of about 0.098 inch,strip width of 15.6 inches, and applied force of 70 pounds per inch ofwidth. The photomicrograph shows the central portion of the stripsandwiched between upper and lower portions without showing the top andbottom surfaces of the strip. The central, lighter band in the stripcorresponds to the central layer 18-6 described above which is partiallydepleted of eutectic forming alloying elements while the outer, darkerportions of the full strip correspond to the upper and lower shells 6-6and 8-6 described above. The grains shown in the strip are globular,indicating absence of working thereof.

It may be beneficial to support the hot strip S exiting the rolls R₁ andR₂ until the strip S cools sufficiently to be self-supporting. Onesupport mechanism is shown FIG. 6 n, and includes a continuous conveyorbelt B positioned beneath the strip S exiting the rolls R₁ and R₂. Thebelt B travels around pulleys P and supports the strip S for apredetermined distance (e.g., about 10 feet). The length of the belt Bbetween the pulleys P may be determined by the casting process, the exittemperature of the strip S and the alloy of the strip S. Suitablematerials for the belt B include fiberglass and metal (e.g. steel) insolid form or as a mesh. Alternatively, as shown in FIG. 6 o, thesupport mechanism may include a stationary support surface H such as ametal shoe over which the strip S travels while it cools. The shoe H maybe made of a material to which the hot strip S does not readily adhere.In certain instances where the strip S is subject to breakage uponexiting the rolls R₁ and R₂, the strip S may be cooled at locations Ewith a fluid such as air or water. Typically, the strip S exits therolls R₁ and R₂ at about 1100° F. It may be desirable to lower the striptemperature to about 1000° F. within about 8 to 10 inches of the nip N.One suitable mechanism for cooling the strip at locations E to achievethat amount of cooling is described in U.S. Pat. No. 4,823,860. Aseparate quenching apparatus may be used to further quench the strip andachieve the above-noted cooling rates.

In one embodiment, a method comprises quenching of the as-cast sheet. Inthese embodiments, the solutionizing step includes solution heattreating and quenching, where the solution heat treating is accomplisheddue to the continuous casting. The preparing step further comprisesremoving the aluminum alloy sheet from the continuous casting apparatus,and, after the removing step, but before the aluminum alloy sheetreaches a temperature of 700° F., quenching the aluminum alloy sheet,where the quenching reduces the temperature of the aluminum alloy sheetat a rate of at least 100° F. per second, thereby accomplishing thesolutionizing. To accomplish the solutionizing step, the temperature ofthe aluminum alloy sheet exiting the continuous casting apparatus ishigher than the temperature of the aluminum alloy sheet during thequenching step.

In one embodiment, the quenching step is initiated before the aluminumalloy sheet reaches a temperature of 800° F. In another embodiment, thequenching step is initiated before the aluminum alloy sheet reaches atemperature of 900° F. In yet another embodiment, the quenching step isinitiated before the aluminum alloy sheet reaches a temperature of 1000°F. In another embodiment, the quenching step is initiated before thealuminum alloy sheet reaches a temperature of 1100° F.

In one embodiment, the quenching step reduces the temperature of thealuminum alloy sheet at a rate of at least 200° F. per second. Inanother embodiment, the quenching step reduces the temperature of thealuminum alloy sheet at a rate of at least 400° F. per second. In yetanother embodiment, the quenching step reduces the temperature of thealuminum alloy sheet at a rate of at least 800° F. per second. Inanother embodiment, the quenching step reduces the temperature of thealuminum alloy sheet at a rate of at least 1600° F. per second. In yetanother embodiment, the quenching step reduces the temperature of thealuminum alloy sheet at a rate of at least 3200° F. per second. Inanother embodiment, the quenching step reduces the temperature of thealuminum alloy sheet at a rate of at least 6400° F. per second. In yetanother embodiment, the quenching step reduces the temperature of thealuminum alloy sheet at a rate of at least 10,000° F. per second.

The quenching step may be accomplished to bring the aluminum alloy sheetto a low temperature (e.g., due to a subsequent cold working step). Inone embodiment, the quenching comprises cooling the aluminum alloy sheetto a temperature of not greater than 200° F. (i.e., the temperature ofthe aluminum alloy sheet upon completion of the quenching step is notgreater than 200° F.). In another embodiment, the quenching comprisescooling the aluminum alloy sheet to a temperature of not greater than150° F. In yet another embodiment, the quenching comprises cooling thealuminum alloy sheet to a temperature of not greater than 100° F. Inanother embodiment, the quenching comprises cooling the aluminum alloysheet to ambient temperature.

The quenching step may be accomplished via any suitable cooling medium.In one embodiment, the quenching comprises contacting the aluminum alloysheet with a gas. In one embodiment, the gas is air. In one embodiment,the quenching comprises contacting the aluminum alloy sheet with aliquid. In one embodiment, the liquid is aqueous based, such as water oranother aqueous based cooling solution. In one embodiment, the liquid isan oil. In one embodiment, the oil is hydrocarbon based. In anotherembodiment, the oil is silicone based.

In some embodiments, the quenching is accomplished via a quenchingapparatus downstream of the continuous casting apparatus. In otherembodiments, ambient air cooling is used.

c. Twin-Roll Continuous Casting—Continuous Casting with ParticulateMatter

In one embodiment, the twin-roll casting apparatus and processes maygenerate an aluminum alloy product having particulate matter therein.The particulate matter can be any non-metallic material such as aluminumoxide, boron carbide, silicon carbide and boron nitride or a metallicmaterial created in-situ during casting or added to a molten aluminumalloy. For purposes of this embodiment, the terms “upper”, “lower”,“right”, “left”, “vertical”, “horizontal,” “top”, “bottom”, andderivatives thereof shall relate to the disclosure, as it is oriented inthe drawing FIGS. 6 p through 6 s, as applicable.

Referring now to FIG. 6 p, in this embodiment the casting/solutionizingstep 142 may include continuously casting strips with particulate matterthere is provided. In step 1006, a molten aluminum alloy containingparticulate matter may be delivered to a casting apparatus, such as thecasting apparatus described above relative to FIGS. 6 b-1 and 6 b-2. Instep 1026, the casting apparatus may rapidly cool at least a portion ofthe molten metal to solidify an outer region (also referred to as anarea, shell, and layer) of the molten metal, and inner region (alsoreferred to as an area, shell, and layer) enriched with particulatematter. The solidified outer regions may increase in thickness as thealloy is cast.

The product exiting the casting apparatus may be a single-layeredproduct and may include the solid inner regions formed in step 1026containing the particulate matter sandwiched within the outer solidregions. The single-layered product can be generated in various formssuch as but not limited to a sheet, a plate, or a foil. In extrusioncasting, the product may be in the form of a wire, rod, bar or otherextrusion.

Similar to FIG. 6 b-2, but referring now to FIG. 6 q, the moltenaluminum alloy metal M containing particulate matter 100-6 may beprovided between rolls R₁ and R₂ of the roll caster. One skilled in theart would understand that the rolls R₁ and R₂ are the casting surfacesof the roll caster. Typically, R₁ and R₂ are cooled to aid in thesolidification of the molten metal M, which directly contacts the rollsR₁ and R₂ at regions 2-6 and 4-6, respectively. Upon contact with therolls R₁ and R₂, the metal M begins to cool and solidify. The coolingmetal solidifies as a first region or shell 6-6 of solidified metaladjacent the roll R₁ and a second region or shell 8-6 of solidifiedmetal adjacent to the roll R₂. The thickness of each of the region orshell 8-6 and 6-6 increases as the metal M advances towards the nip N.Initially, the particulate matter 100-6 may be located at the interfacesbetween each of the first and second regions 8-6 and 6-6 and the moltenmetal M. As the molten metal M travels between the opposing surfaces ofthe cooled rolls R₁, R₂, the particulate matter 100-6 may be draggedinto a central region (or portion) 12-6, also referred to in thisembodiment as an “inner portion,” of the slower moving flow of themolten metal M and may be carried in the direction of arrows C₁ and C₂.In the central region 12 upstream of the nip N referred to as region16-6, the metal M is semi-solid and includes a particulate matter 100-6component and a molten metal M component. The molten metal M in theregion 16-6 may have a mushy consistency due in part to the dispersionof the particulate matter 100-6 therein. The forward rotation of therolls R₁ and R₂ at the nip N advances substantially only the solidportion of the metal, i.e. the first and second regions 6-6 and 8-6 andthe particulate matter in the central region 12-6 while forcing moltenmetal M in the central region 12-6 upstream from the nip N such that themetal is substantially solid (and alternatively completely solid) as itleaves the point of the nip N. Downstream of the nip N, the centralregion 12-6 is a solid central region (or layer) 18-6 containingparticulate matter 100-6 sandwiched between the first region 6-6 and theregion shell 8-6. For clarity, the single-layer,single-continuously-cast aluminum article described above having acentral layer or region 18-6 with a high concentration of particulatematter 100-6 sandwiched between the first and second regions 6-6 and 8-6shall also be referred to as a functionally graded MMC structure. Thesize of the particulate matter 100-6 in the central layer 18-6 may be atleast 30 microns. In a strip product, the solid inner region (orportion) may constitute 20 to 30 percent of the total thickness of thestrip. While the caster of FIG. 6 q is shown as producing strip 20-6 ina generally horizontal orientation, this is not meant to be limiting asthe strip 20-6 may exit the caster at an angle or vertically.

The casting process described in relation to FIG. 6 q follows the methodsteps outlined above in FIG. 6 p. Molten metal delivered in step 1006 tothe roll caster begins to cool and solidify in step 1026. The coolingmetal develops outer layers of solidified metal, i.e. first and secondregions 6-6 and 8-6, near or adjacent the cooled casting surfaces R₁,R₂. As stated in the preceding paragraphs, the thickness of the firstregion (or shell) 6-6 and the second region (or shell) 8-6 increases asthe metal advances through the casting apparatus. Per step 1026, theparticulate matter 100-6 may be drawn into the central portion 12-6,which is partially surrounded by the solidified outer regions 6-6 and8-6. In FIG. 6 q, the first and second regions 6-6 and 8-6 substantiallysurround the central region 18-6. In other words, the central region18-6 that contains the particulate matter 100-6 is located between thefirst region 6-6 and the second region 8-6, within a single-layeredproduct along a concentration gradient. Said differently, the centralregion 18-6 is sandwiched between the first shell 6-6 and the secondshell 8-6. In other casting apparatuses, the first and/or second shellsmay completely surround the inner layer. After step 1026, the centralregion 18-6 may be solidified to produce an inner region (or layer).Prior to complete solidification, the central region 12-6 of the strip20-6 is semi-solid and includes a particulate matter component and amolten metal component. The metal at this stage has a mushy consistencydue in part to the dispersion of particulate matter therein.

Sometime after step 1026, the product is completely solidified andincludes the inner region (or layer), which contains the particulatematter and a first and second shell, i.e. outer regions or layers, thatsubstantially surrounds the inner region (or layer). The thickness ofthe inner region (or layer) may be about 10-40% of the thickness of theproduct. In an alternative embodiment, the inner region (or layer) maybe comprised of about 70% particulate matter 100-6 by volume, while thefirst and second shells are each independently comprised of about 15%particulate matter 100-6 by volume. In a still further embodiment, theinner region (or layer) may be comprised of at least 70% particulatematter 100-6 by volume, while the first and second shells are eachindependently comprised of less than 15% particulate matter 100-6 byvolume.

During casting, movement of the particulate matter 100-6 into the innerregion may be caused by the shear forces that result from the speeddifferences between the inner regions of molten metal and the solidifiedouter regions. In order to facilitate movement into the inner region,the roll casters may be operated at speeds of at least 30 fpm,alternatively at least 40 fpm, and alternatively at least 50 fpm (feetper minute). In other words, during casting, particulate matter 100-6having a size of at least 30 microns moves from being evenly distributedto a more concentrated state, i.e., into the inner region duringcasting. Without wishing to be bound by the theory, it is believed thatroll casters operated at speeds of less than 10 feet per minute do notgenerate the shear forces required to move the particulate matter (whichhas a size of at least 30 microns) into the inner region (or layer).

The control, maintenance and selection of the appropriate speed of therolls R₁ and R₂ may impact the operability of the casting apparatus. Theroll speed determines the speed that the molten metal M advances towardsthe nip N. If the speed is too slow, the particulate matter 100-6 maynot experience sufficient forces to become entrained in the centralportion 18-6 of the metal product. In one embodiment, the apparatus isoperated at speeds ranging from 50 to 300 feet per minute. The linearspeed that molten aluminum is delivered to the rolls R₁ and R₂ may beless than the speed of the rolls R₁ and R₂, or about one quarter of theroll speed.

Referring now to FIG. 6 r, depicted therein is a microstructure of afunctionally graded MMC cast in accordance with the present disclosure.The strip 400-6 shown comprises 15% alumina by weight and is at 0.004inch gauge. The particulate matter 410-6 can be seen distributedthroughout the strip 400-6 with a higher concentration of particulatesconcentrated in a central region (or layer or portion) 401-06 whilelower concentrations can be seen in outer regions (or layers or shells)402-06 and 403-06 respectively. It is believed that, without wishing tobe bound by the same, there is no reaction between the particulatematter 410-6 and the aluminum matrix due to the rapid solidification ofthe molten during casting. Moreover, there is no damage at the interfacebetween the particulate and the metal matrix as may be seen in FIG. 6 s.Because the particulate matter does not protrude above the surface ofthe product it does not wear or abrade the rolling mill rolls.

d. Twin-Roll Continuous Casting—Continuous Casting of Immiscible Metals

In another embodiment, the twin-roll casting apparatus and processes maygenerate an aluminum alloy product having immiscible phases therein.Suitable immiscible phase elements include Sn, Pb, Bi, and Cd and may bepresent in the amounts disclosed below in the Compositions section(Section G), below. For purposes of this embodiment, the terms “upper”,“lower”, “right”, “left”, “vertical”, “horizontal,” “top”, “bottom”, andderivatives thereof shall relate to the disclosure, as it is oriented inthe drawing FIGS. 6 t through 6 x, as applicable.

Referring now to FIG. 6 t, in this embodiment the casting/solutionizingstep 142 may include continuously casting strips with at least oneimmiscible phase therein is provided. In step 1046, a molten aluminumalloy and at least one immiscible phase element are introduced into asuitable casting apparatus, such as the casting apparatus describedabove relative to FIGS. 6 b-1 and 6 b-2. In step 1066, the castingapparatus is operated at a casting speed ranging from 50 to 300 feet perminute.

The process will now be illustrated with respect to the apparatusdepicted in FIGS. 6 u-6 w, but is also applicable to the equipmentdepicted in FIGS. 6 b-1, 6 b-2, 6 n, 6 o, 6 q, and 7 a-7 b, among othertypes of continuous casting apparatus. As is depicted in FIG. 6 u, theapparatus includes a pair of endless belts 1067 and 1267 that act ascasting molds carried by a pair of upper pulleys 1467 and 1667 and apair of corresponding lower pulleys 1867 and 2067. Each pulley may bemounted for rotation about an axis 2167, 2267, 2467, and 2667respectively. The pulleys may be of a suitable heat resistant type, andeither or both of the upper pulleys 1467 and 1667 is driven by asuitable motor means (not shown). The same is true for the lower pulleys1867 and 2067. Each of the belts 1067 and 1267 is an endless belt, andis generally formed of a metal which has low reactivity or isnon-reactive with the metal being cast. Good results have been achievedusing steel and copper alloy belts, but other belts can also be usedsuch as aluminum. It should be noted that in this embodiment of theinvention casting molds are implemented as casting belts 1067 and 1267.However casting molds can comprise a single mold, one or more rolls or aset of blocks for example.

The pulleys are positioned, as illustrated in FIGS. 6 u and 6 v, oneabove the other with a molding gap therebetween. The gap is dimensionedto correspond to the desired thickness of the metal strip being cast.Thus, the thickness of the metal strip being cast is determined by thedimensions of the nip between belts 1067 and 1267 passing over pulleys1467 and 1867 along a line passing through the axis of pulleys 1467 and1867 which is perpendicular to the casting belts 1067 and 1267. Moltenmetal to be cast may be supplied to the molding zone through metalsupply means 2867 such as a tundish. The interior of tundish 2867corresponds in width to the width of the product to be cast, and canhave a width up to the width of the narrower of the casting belts 1067and 1267. The tundish 28 includes a metal supply delivery casting tip3067 to deliver a horizontal stream of molten metal to the molding zonebetween the belts 1067 and 1267.

Thus, the tip 3067, as shown in FIG. 6 v, defines, along with the belts1067 and 1267 immediately adjacent to tip 3067, a molding zone intowhich the horizontal stream of molten metal flows. Thus, the stream ofmolten metal flowing substantially horizontally from the tip fills themolding zone between the curvature of each belt 1067 and 1267 to the nipof the pulleys 1467 and 1867. It begins to solidify and is substantiallysolidified by the point at which the cast strip reaches the nip ofpulleys 1467 and 1867. Supplying the horizontally flowing stream ofmolten metal to the molding zone where it is in contact with a curvedsection of the belts 1067 and 1267 passing about pulleys 1467 and 1867serves to limit distortion and thereby maintain better thermal contactbetween the molten metal and each of the belts as well as improving thequality of the top and bottom surfaces of the cast strip.

The casting apparatus shown in FIGS. 6 u-6 w may include a pair ofcooling apparatus 3267 and 3467 positioned opposite that portion of theendless belt in contact with the metal being cast in the molding gapbetween belts 1067 and 1267. The cooling means 3267 and 3467 thus serveto cool the belts 1067 and 1267 just after they pass over pulleys 1667and 2067, respectively, and before they come into contact with themolten metal. As illustrated in FIGS. 6 u and 6 w, the coolers 3267 and3467 are positioned as shown on the return run of belts 1067 and 1267,respectively. The cooling apparatus 3267 and 3467 can be conventionalcooling apparatus, such as fluid cooling tips positioned to spray acooling fluid directly on the inside and/or outside of belts 1067 and1267 to cool the belts through their thicknesses.

Thus, molten metal flows horizontally from the tundish through thecasting tip 3067 into the casting or molding zone defined between thebelts 1067 and 1267 where the belts 1067 and 1267 are heated by heattransfer from the cast strip to the belts 1067 and 1267. The cast metalstrip remains between and is conveyed by the casting belts 1067 and 1267until each of them is turned past the centerline of pulleys 1667 and2067. Thereafter, in the return loop, the cooling apparatus 3267 and3467 cool the belts 1067 and 1267, respectively, and remove therefromsubstantially all of the heat transferred to the belts in the moldingzone. The supply of molten metal from the tundish through the castingtip 3067 is shown in greater detail in FIG. 6 w, where the casting tip3067 is formed of an upper wall 4067 and a lower wall 4267 defining acentral opening 4467 therebetween whose width may extend substantiallyover the width of the belts 1067 and 1267.

The distal ends of the walls 4067 and 4267 of the casting tip 3067 areproximal the surface of the casting belts 1067 and 1267, respectively,and define with the belts 1067 and 1267 a casting cavity or molding zone4667 into which the molten metal flows through the central opening 4467.As the molten metal in the casting cavity 4667 flows between the belts1067 and 1267, it transfers its heat to the belts 1067 and 1267,simultaneously cooling the molten metal to form a solid strip 5067maintained between casting belts 1067 and 1267. Sufficient setback(defined as the distance between first contact 4767 of the molten metal4667 and the nip 4867 defined as the closet approach of the entrypulleys 1467 and 1867) is provided to allow substantially completesolidification prior to the nip 4867.

In operation, a molten aluminum alloy comprising a phase that isimmiscible in the liquid state is introduced via tundish 2867, throughcasting tip 3067, and into the casting zone defined between belts 1067and 1267. In one embodiment, the dimensions of the nip between belts1067 and 1267 passing over pulleys 1467 and 1867 is in the range of 0.08to 0.249 inches, and the casting speed is 50-300 fpm. Under theseconditions, droplets of the immiscible liquid phase may nucleate aheadof the solidification front and may be engulfed by the rapidly movingfreeze front into the space between the secondary dendrite arm (“SDA”)spaces. Thus, the resulting cast strip may contain a uniformdistribution of the droplets of the immiscible phase.

Turning now to FIG. 6 x, a photomicrograph of a section of a Al-6Sn(aluminum alloy having 6 percent by weight tin) strip 40067 produced inaccordance with the present invention is shown. The strip shows auniform distribution of fine Sn particles 40167 which are 3 micrometersor smaller. This result is several times smaller than particles thatwould result from material made from an ingot or by roll casting whichare typically from 40 microns to 400 microns in size

B. Cold Working

Referring back to FIG. 2 a, and as noted above, the new process includescold working (200) the aluminum alloy body a high amount. “Cold working”and the like means deforming an aluminum alloy body in at least onedirection and at temperatures below hot working temperatures (e.g., notgreater than 400° F.). Cold working may be imparted by one or more ofrolling, extruding, forging, drawing, ironing, spinning, flow-forming,and combinations thereof, among other types of cold working methods.These cold working methods may at least partially assist in producingvarious Al—Li alloy products (see, Product Applications, below).

i. Cold Rolling

In one embodiment, and with reference now to FIG. 9, the cold workingstep (200) comprises cold rolling (220) (and in some instances consistsof cold rolling (220), with optional stretching or straightening forflatness (240)). In this embodiment, and as described above, the coldrolling step (220) is completed after the solutionizing step (140). Coldrolling (220) is a fabrication technique where an aluminum alloy body isdecreased in thickness, generally via pressure applied by rollers, andwhere the aluminum alloy body enters the rolling equipment at atemperature below that used for hot rolling (124) (e.g., not greaterthan 400° F.). In one embodiment, the aluminum alloy body enters therolling equipment at ambient conditions, i.e., the cold rolling step(220) is initiated at ambient conditions in this embodiment.

The cold rolling step (220) reduces the thickness of an Al—Li alloy bodyby at least 25%. The cold rolling step (220) may be completed in one ormore rolling passes. In one embodiment, the cold rolling step (220)rolls the aluminum alloy body from an intermediate gauge to a finalgauge. The cold rolling step (220) may produce a sheet, plate, or foilproduct. A foil product is a rolled product having a thickness of lessthan 0.006 inch. A sheet product is a rolled product having a thicknessof from 0.006 inch to 0.249 inch. A plate product is a rolled producthaving a thickness of 0.250 inch or greater.

“Cold rolled XX %” and the like means XX_(CR) %, where XX_(CR) % is theamount of thickness reduction achieved when the aluminum alloy body isreduced from a first thickness of T₁ to a second thickness of T₂ by coldrolling, where T₁ is the thickness prior to the cold rolling step (200)(e.g., after solutionizing) and T₂ is the thickness after the coldrolling step (200). In other words, XX_(CR) % is equal to:

XX _(CR)%=(1−T ₂ /T ₁)*100%

For example, when an aluminum alloy body is cold rolled from a firstthickness (T₁) of 15.0 mm to a second thickness of 3.0 mm (T₂), XX_(CR)% is 80%. Phrases such as “cold rolling 80%” and “cold rolled 80%” areequivalent to the expression XX_(CR) %=80%.

In one embodiment, the aluminum alloy body is cold rolled (220) at least30% (XX_(CR) %≧30%), i.e., is reduced in thickness by at least 30%. Inother embodiments, the aluminum alloy body is cold rolled (220) at least35% (XX_(CR) %≧35%), or at least 40% (XX_(CR) %≧40%), or at least 45%(XX_(CR) %≧45%), or at least 50% (XX_(CR) %≧50%), or at least 55%(XX_(CR) %≧55%), or at least 60% (XX_(CR) %≧60%), or at least 65%(XX_(CR) %≧65%), or at least 70% (XX_(CR) %≧70%), or at least 75%(XX_(CR) %≧75%), or at least 80% (XX_(CR) %≧80%), or at least 85%(XX_(CR) %≧85%), or at least 90% (XX_(CR) %≧90%), or more.

In some embodiments, it may be impractical or non-ideal to cold roll(220) by more than 90% (XX_(CR) %≦90%). In these embodiments, thealuminum alloy body may be cold rolled (220) by not greater than 87%(XX_(CR) %≦87%), such as cold rolled (220) not more than 85% (XX_(CR)%≦85%), or not greater than 83% (XX_(CR) %≦83%), or not greater than 80%(XX_(CR) %≦80%).

In one embodiment, the aluminum alloy body is cold rolled in the rangeof from more than 50% to not greater than 85% (50%<XX_(CR) %≦85%). Thisamount of cold rolling may produce an aluminum alloy body havingpreferred properties. In a related embodiment, the aluminum alloy bodymay be cold rolled in the range of from 55% to 85% (55%≦XX_(CR) %≦85%).In yet another embodiment, the aluminum alloy body may be cold rolled inthe range of from 60% to 85% (60%≦XX_(CR) %≦85%). In yet anotherembodiment, the aluminum alloy body may be cold rolled in the range offrom 65% to 85% (65%≦XX_(CR) %≦85%). In yet another embodiment, thealuminum alloy body may be cold rolled in the range of from 70% to 80%(70%≦XX_(CR) %≦80%).

Still referring to FIG. 9, in this embodiment of the process, optionalpre-cold rolling (128) may be completed. This pre-cold rolling step(128) may further reduce the intermediate gauge of the aluminum alloybody (due to the hot rolling 126) to a secondary intermediate gauge. Asan example, the optional cold rolling step (128) may be used to producea secondary intermediate gauge that facilitates production of a finalcold rolled gauge during the cold rolling step (220).

ii. Other Cold Working Techniques

Aside from cold rolling, and referring back to FIG. 2 a, cold workingmay be imparted by one or more of extruding, forging, drawing, ironing,spinning, flow-forming, and combinations thereof, among other types ofcold working methods, alone or in combination with cold rolling. Asnoted above, the aluminum alloy body is generally cold worked by atleast 25% after solutionizing. In one embodiment, the cold working worksthe aluminum alloy body to its substantially final form (i.e., noadditional hot working and/or cold working steps are required to achievethe final product form).

“Cold working by XX %” (“XX_(CW) %”) and the like means cold working thealuminum alloy body an amount sufficient to achieve an equivalentplastic strain (described below) that is at least as large as the amountof equivalent plastic strain that would have been achieved if thealuminum alloy body had been cold rolled XX % (XX_(CR) %). For example,the phrase “cold working 68.2%” means cold working the aluminum alloybody an amount sufficient to achieve an equivalent plastic strain thatis at least as large as the amount of equivalent plastic strain thatwould have been achieved if the aluminum alloy body had been cold rolled68.2%. Since XX_(CW) % and XX_(CR) % both refer to the amount ofequivalent plastic strain induced in an aluminum alloy body as if thealuminum alloy body was cold rolled XX % (or actually is cold rolled XX% in the case of actual cold rolling), those terms are usedinterchangeably herein to refer to this amount of equivalent plasticstrain.

Equivalent plastic strain is related to true strain. For example, coldrolling XX %, i.e., XX_(CR) %, may be represented by true strain values,where true strain (ε_(true)) is given by the formula:

ε_(true)=ln(1−%CR/100)  (1)

Where % CR is XX_(CR) %, true strain values may be converted toequivalent plastic strain values. In the case where biaxial strain isachieved during cold rolling, the estimated equivalent plastic strainwill be 1.155 times greater than the true strain value (2 divided by the√3 equals 1.155). Biaxial strain is representative of the type ofplastic strain imparted during cold rolling operations. A tablecorrelating cold rolling XX % to true strain values and equivalentplastic strain values is provided in Table 1, below.

TABLE 1 Cold Rolling Thickness Reduction Cold Rolling EstimatedEquivalent (XX_(CR) %) True Strain Value Plastic Strain 25% 0.28770.3322 30% 0.3567 0.4119 35% 0.4308 0.4974 40% 0.5108 0.5899 45% 0.59780.6903 50% 0.6931 0.8004 55% 0.7985 0.9220 60% 0.9163 1.0583 65% 1.04981.2120 70% 1.2040 1.3902 75% 1.3863 1.6008 80% 1.6094 1.8584 85% 1.89712.1906 90% 2.3026 2.6588These equivalent plastic strain values assume:

A. no elastic strain;

B. the true plastic strains preserve volume constancy; and

C. the loading is proportional.

For proportional loading, the above and/or other principles may be usedto determine an equivalent plastic strain for various cold workingoperations. For non-proportional loading, the equivalent plastic straindue to cold working may be determined using the formula:

$\begin{matrix}{{d\; ɛ_{p}} = {\frac{\sqrt{2}}{3}\left\lbrack \sqrt{\left( {{d\; ɛ_{1}^{p}} - {d\; ɛ_{2}^{p}}} \right)^{2} + \left( {{d\; ɛ_{1}^{p}} - {d\; ɛ_{3}^{p}}} \right)^{2} + \left( {{d\; ɛ_{3}^{p}} - {d\; ɛ_{2}^{p}}} \right)^{2}} \right\rbrack}} & (2)\end{matrix}$

where de_(p) is the equivalent plastic strain increment and dε_(i) ^(p)(i=1,2,3) represent the increment in the principal plastic straincomponents. See, Plasticity, A. Mendelson, Krieger Pub Co; 2nd edition(August 1983), ISBN-10: 0898745829.

Those skilled in the art appreciate that the cold working step (200) mayinclude deforming the aluminum alloy body in a first manner (e.g.,compressing) and then deforming the aluminum alloy body in a secondmanner (e.g., stretching), and that the equivalent plastic straindescribed herein refers to the accumulated strain due to all deformationoperations completed as a part of the cold working step (200).Furthermore, those skilled in the art appreciate that the cold workingstep (200) will result in inducement of strain, but not necessarily achange in the final dimensions of the aluminum alloy body. For example,an aluminum alloy body may be cold deformed in a first manner (e.g.,compressing) after which it is cold deformed in a second manner (e.g.,stretching), the accumulated results of which provide an aluminum alloybody having about the same final dimensions as the aluminum alloy bodybefore the cold working step (200), but with an increased strain due tothe various cold deformation operations of the cold working step (200).Similarly, high accumulated strains can be achieved through sequentialbending and reverse bending operations.

The accumulated equivalent plastic strain, and thus XX_(CR) %, may bedetermined for any given cold working operation, or series of coldworking operations, by computing the equivalent plastic strain impartedby those cold working operations and then determining its correspondingXX_(CR) % value, via the methodologies shown above, and othermethodologies known to those skilled in the art. For example, analuminum alloy body may be cold drawn, and those skilled in the art maycompute the amount of equivalent plastic strain imparted to the aluminumalloy body based on the operation parameters of the cold drawing. If thecold drawing induced, for example, an equivalent plastic strain of about0.9552, then this cold drawing operation would be equivalent to anXX_(CR) % of about 56.3% (0.9552/1.155 equals a true strain value of0.8270 (ε_(true)); in turn, the corresponding XX_(CR) % is 56.3% usingequation (1), above). Thus, in this example, XX_(CR) %=56.3, even thoughthe cold working was cold drawing and not cold rolling. Furthermore,since “cold working by XX %” (“XX_(CW) %”) is defined (above) as coldworking the aluminum alloy body an amount sufficient to achieve anequivalent plastic strain that is at least as large as the amount ofequivalent plastic strain that would be achieved if the aluminum alloybody had been reduced in thickness XX % solely by cold rolling (“XX_(CR)%”), then XX_(CW) is also 56.3%. Similar calculations may be completedwhen a series of cold working operations are employed, and in thosesituations the accumulated equivalent plastic strain due to the seriesof cold working operations would be used to determine the XX_(CR) %.

As described earlier, the cold working (200) is accomplished such thatthe aluminum alloy body realizes an XX_(CW) % or XX_(CR) %≧25%, i.e.,≧0.3322 equivalent plastic strain. “Cold working XX %” and the likemeans XX_(CW) %. Phrases such as “cold working 80%” and “cold worked80%” are equivalent to the expression XX_(CW) %=80. For tailorednon-uniform cold working operations, the amount of equivalent plasticstrain, and thus the amount of XX_(CW) or XX_(CR), is determined on theportion(s) of the aluminum alloy body receiving the cold work (200).

In one embodiment, the aluminum alloy body is cold worked (200)sufficiently to achieve, and realizes, an equivalent plastic strain(“EPS”) of at least 0.4119 (i.e., XX_(CW) %≧30%). In other embodiments,the aluminum alloy body is cold worked (200) sufficiently to achieve,and realizes, an EPS of at least 0.4974 (XX_(CW) %≧35%), or at least0.5899 (XX_(CW) %≧40%), or at least 0.6903 (XX_(CW) %≧45%), or at least0.8004, (XX_(CW) %≧50%), or at least 0.9220 (XX_(CW) %≧55%), or at least1.0583 (XX_(CW) %≧60%), or at least 1.2120 (XX_(CW) %≧65%), or at least1.3902 (XX_(CW) %≧70%), or at least 1.6008 (XX_(CW) %≧75%), or at least1.8584 (XX_(CW) %≧80%), or at least 2.1906 (XX_(CW) %≧85%), or at least2.6588 (XX_(CW) %≧90%), or more.

In some embodiments, it may be impractical or non-ideal to cold work(200) by more than 90% (XX_(CW) %≦90% and EPS≦2.6588). In theseembodiments, the aluminum alloy body may be cold worked (200) not morethan 87% (XX_(CW) %≦87% and EPS≦2.3564), such as cold worked (200) notmore than 85% (XX_(CW) %≦85% and EPS≦2.1906), or not more than 83%(XX_(CW) %≦83% and EPS≦2.0466), or not more than 80% (XX_(CW) %≦80% andEPS≦1.8584).

In one embodiment, the aluminum alloy body is cold worked (200) in therange of from more than 50% to not greater than 85% (50%≦XX_(CW) %≦85%).This amount of cold working (200) may produce an aluminum alloy bodyhaving preferred properties. In a related embodiment, the aluminum alloybody is cold worked (200) in the range of from 55% to 85% (55%≦XX_(CW)%≦85%). In yet another embodiment, the aluminum alloy body is coldworked (200) in the range of from 60% to 85% (60%≦XX_(CW) %≦85%). In yetanother embodiment, the aluminum alloy body is cold worked (200) in therange of from 65% to 85% (65%≦XX_(CW) %≦85%). In yet another embodiment,the aluminum alloy body is cold worked (200) in the range of from 70% to80% (70%≦XX_(CW) %≦80%).

iii. Gradients

The cold working step (200) may be tailored to deform the aluminum alloybody in a generally uniform manner, such as via rolling, describedabove, or conventional extruding processes, among others. In otherembodiments, the cold working step may be tailored to deform thealuminum alloy body in a generally non-uniform manner. Thus, in someembodiments, the process may produce an aluminum alloy body havingtailored cold working gradients, i.e., a first portion of the aluminumalloy body receives a first tailored amount of cold work and a secondportion of the aluminum alloy body receives a second tailored amount ofcold work, where the first tailored amount is different than the secondtailored amount. Examples of cold working operations (200) that may becompleted, alone or in combination, to achieve tailored non-uniform coldwork include forging, burnishing, shot peening, flow forming, andspin-forming, among others. Such cold working operations may also beutilized in combination with generally uniform cold working operations,such as cold rolling and/or extruding, among others. As mentioned above,for tailored non-uniform cold working operations, the amount ofequivalent plastic strain is determined on the portion(s) of thealuminum alloy body receiving the cold work (200). Thus, after thethermal treatment step (300), such products may have a first portionhaving a first strength and a second portion having a second strength,with the first strength being different than the second strength.

Tailored products may be useful, for example, in situations where higherstrength is required in one part of a material, but lower strengthand/or higher ductility may be required in another part of a material.For example, an automotive component or aerospace component may haveforming requirements, such as tight bend radii and/or deep drawrequirements around its perimeter, but may also require high strengthwere it is attached to other components (e.g., via bolting, riveting orwelding). Typically, these two characteristics oppose each other.However, with the use of selective strengthening, a single panel couldmeet both requirements.

As described in further detail below, tailored cold working may be usedto produce a monolithic aluminum alloy body (e.g., a sheet, plate, ortubulars) having a first portion and a second portion, wherein the firstportion has at least 25% cold work, and wherein second portion has atleast 5% less cold work than the first portion, i.e., the first andsecond portions have different amounts of induced cold work (e.g., seeFIGS. 2 b-2 m, described below). In the context of this subsection(B)(iii) “at least XX % less cold work” and the like means that the XX %value is subtracted from the first cold work percent value. For example,when a second portion has at least XX % less cold work than a firstportion having at least YY % cold work, the second portion would have acold work of ≦YY %-XX %.

In one embodiment, the second portion is adjacent the first portion(e.g., see FIG. 2 j, below). For purposes of this subsection (B)(iii),“adjacent” means near or close to, but not necessarily touching. In oneembodiment, an adjacent second portion touches the first portion. Inanother embodiment, the second portion is not adjacent and is remote ofthe first portion, such as when the first portion is a first end of themonolithic aluminum alloy body and the second portion is a second end ofthe monolithic aluminum alloy body (e.g., see FIGS. 2 b and 2 d,described below).

In one embodiment, the monolithic aluminum alloy body having the firstand second portions is a sheet or plate. In one embodiment, this sheetor plate has a uniform thickness (e.g., see FIGS. 2 d, 2 e, 2 g, 2 h, 2j, and 2 k, described below). In another embodiment, the sheet or platehas a non-uniform thickness, where the first portion is associated witha first thickness of the sheet or plate, and the second portion isassociated with a second thickness of the sheet or plate (e.g., seeFIGS. 2 i and 2 l, described below).

In one embodiment, the first portion of the monolithic aluminum alloybody has at least 30% cold work. In other embodiments, the first portionhas at least 35% cold work, such as at least 40% cold work, or at least45% cold work, or at least 50% cold work, or at least 55% cold work, orat least 60% cold work, or at least 65% cold work, or at least 70% coldwork, or at least 75% cold work, or at least 80% cold work, or at least85% cold work, or at least 90% cold work, or more. In any of theseembodiments, the second portion may have at least 10% less cold workthan the first portion. In one of these embodiments, the second portionmay have at least 15% less cold work than the first portion. In othersof these embodiments, the second may have at least 20% less cold workthan the second portion, or at least 25% less cold work, or at least 30%less cold work, or at least 35% less cold work, or at least 40% lesscold work, or at least 45% less cold work, or at least 50% less coldwork, or at least 55% less cold work, or at least 60% less cold work, orat least 65% less cold work, or at least 70% less cold work, or at least75% less cold work, or at least 80% less cold work, or at least 85% lesscold work, or at least 90% less cold work, than the first portion. Inone embodiment, the second portion receives no cold work during the coldworking operation.

In one embodiment, the first portion of the monolithic aluminum alloybody has at least 5% higher strength (tensile yield strength and/orultimate tensile strength) as compared to the second portion. In otherembodiments the first portion of the monolithic aluminum alloy body hasat least 10% higher, or at least 20% higher, or at least 30% higher, orat least 40% higher, at least 50% higher, or at least 60% higher, or atleast 70% higher, or at least 80% higher, at least 90% higher, or atleast 100% higher (2×) or more as compared to the second portion. In oneembodiment, the first portion has an elongation of at least 4%. In otherembodiments, the first portion has an elongation of at least 6%, or atleast 8%, or at least 10%, or at least 12%, or higher. In oneembodiment, the second portion has higher elongation than the firstportion (relates to ductility/formability).

These monolithic aluminum alloy bodies having the first portion and thesecond portion may be formed into a component of an assembly. Acomponent may be formed into a predetermined shaped product (defined inSection F, below). However, it is not required that a component be apredetermined shaped product since a component does not necessarilyrequire forming. In one embodiment, a component having the first portionis a component of an assembly, and the first portion is associated withan attachment point of that assembly, such as an attachment point of amobile apparatus (e.g., of a vehicle) or a stationary apparatus (e.g., abuilding).

In one embodiment, the component is a component of a vehicle. In oneembodiment the component comprises the first portion and the secondportion of the monolithic aluminum alloy body, and the first portion hasa higher strength than the second portion. In one embodiment, thevehicle is an automotive vehicle, and an attachment point relates to a“point-load position” of the vehicle. A “point load position” is aposition characterized by a point load condition, and may relate to amobile body or a stationary body. A “point-load condition” is acondition in a structure (mobile or stationary) characterized by a highload transfer, concentrated at a location. This load transfer may occurat the attachment location(s) of the structure, such as in an areatypically joined by welding, riveting, bolting, and the like. A pointload position may be potentially subjected to high stresses (e.g., acrash event for a ground-based vehicle; wing attachment locations foraerospace vehicles). The following automotive components may be relatedto a point-load position of an automotive vehicle: seat rail attachmentpoints (front and rear), seat belt attachment points, accessoryattachment points (e.g., firewalls), door guard beam attachment points(e.g., hinges, anchor points, locking mechanisms/latches, door guardbeam attachment points), engine mounts, body mounts, shock towers andsuspension control arms, among others. Many of these components areillustrated in FIGS. 2 n-2 o and 2 p-1 to 2 p-3. In another embodiment,the vehicle may be another ground-based vehicle, such as a bus, van,truck tractor, box trailer, flatbed trailer, recreational vehicles(RVs), motorcycles, all-terrain vehicles (ATVs), and the like, and acomponent may be tailored for these vehicles such that the first portionis associated with an attachment point. In another embodiment, thevehicle may be an aerospace vehicle, the component is an aerospacecomponent, and the first portion of the component may be associated withan attachment point of the aerospace vehicle, for example. In anotherembodiment, the vehicle may be a marine vessel, the component is amarine component, and the first portion of the component may beassociated with an attachment point of the marine vehicle. In anotherembodiment, the vehicle may be a rail car or locomotive, the componentis a rail car or locomotive component, and the first portion of thecomponent may be associated with an attachment point of the rail car orlocomotive. These components may be used in other non-vehicleassemblies, such as armor components in a ballistics assembly or acomponent for an offshore platform, for example.

In another embodiment, the monolithic aluminum alloy body having thefirst portion and the second portion may be processed to achieve apredetermined condition, such as any of the predetermined conditionsdescribed in the Thermal Treatment section (Section C(i)), describedbelow. In such embodiments, at least one of the first portion and thesecond portion achieve the predetermined condition (322) so as tofacilitate production of monolithic aluminum alloy bodies havingtailored properties. For example, the first portion may be processed toachieve a first predetermined condition (e.g., a first predeterminedstrength and/or elongation), and the second portion may be processed toachieve a second predetermined condition (e.g., a second predeterminedstrength and/or elongation), wherein the second predetermined conditionis different than the first predetermined condition. In one embodiment,the first portion is processed to a first predetermined strength (e.g.,a predetermined tensile yield strength and/or a predetermined ultimatetensile strength), and the second portion is processed to a secondpredetermined strength, where the first predetermined strength is higherthan the second predetermined strength. In one embodiment, the firstpredetermined strength is at least 5% higher than the secondpredetermined, such as any of strength differentials between the firstand second portions described above. In any of these embodiments, thesecond portion may realize a higher elongation than the first portion.Such aluminum alloy bodies may be useful, for example, to providetailored energy absorption properties, potentially in combination withtailored reinforcement properties. For example, a component made from amonolithic aluminum alloy body having the first portion and the secondportion may be designed and produced such that the second portion isassociated with an energy absorption zone (e.g., with higher ductility,optionally with lower strength) and the first portion is associated witha reinforcement zone (e.g., with higher strength, optionally with lowerductility). Such components may be useful, for example, in automotiveand armor applications, among others. In one embodiment, such acomponent is an automotive component designed for lightweight crashmanagement. Examples of such automotive components include: front crashcans, pillars (e.g., A-pillars, B-pillars), rocker or sill panels, frontupper rails (shotgun), lower longitudinals, windshield headers, upperroof siderails, seat rails, door guard beams, rear longitudinals, anddoor panels, among others. Many of these components are illustrated inFIGS. 2 n-2 o and 2 p-1 to 2 p-3.

As described above, the second portion may be adjacent the firstportion. In other embodiments, the second portion is remote of the firstportion. In some of the latter embodiments, the first portion is a firstend of the monolithic aluminum alloy body and the second portion is asecond end of the monolithic aluminum alloy body, wherein the first endcomprises at least 25% cold work, and wherein second end has at least 5%less cold work as compared to the first end. In another embodiment, suchbodies may be of non-uniform thickness, where the first end has a firstthickness, the second end has a second thickness, and the firstthickness is at least 10% thinner than the second thickness. Such bodiesmay alternatively have a uniform thickness where the first end has afirst thickness, the second end has a second thickness, and where thefirst thickness is within 3% of the second thickness (e.g., within 1% ofthe second thickness, or within 0.5% of the second thickness, or within0.1% of the second thickness, or less). In either embodiment, thealuminum alloy body may have a middle portion separating the first endand the second end. In one embodiment, the amount of cold work in themiddle portion tapers from the first end to the second end, or viceversa (e.g., see FIGS. 2 b, 2 d and 2 i, described below). In oneembodiment, the middle portion generally uniformly tapers from the firstend to the second end (e.g., see FIGS. 2 b and 2 d). In anotherembodiment, the amount of cold work non-uniformly changes from the firstend to the second (e.g., see FIGS. 2 c, 2 e and 2 f, described below).In one embodiment the first end and the second ends are associated withthe longitudinal direction of the monolithic aluminum alloy body, andthus properties may be tailored relative to in the “L” direction of theproduct. In another embodiment, the first end and the second ends areassociated with the transverse direction of the sheet or plate, and thusproperties may be tailored relative to in the “LT” or transversedirection of the product.

The first and/or second portions may achieve improved properties, suchas any of the properties listed in the properties listed in theProperties section (Section H), below. In one embodiment, both the firstand second portions achieve an improvement in strength as compared toone or more of (a) the aluminum alloy body in the as-cold workedcondition and (b) a reference version of aluminum alloy body in one theT6 temper, such as any of the improved strength properties/values listedin the Properties section (Section H), below. The terms “as-cold workedcondition”, and “a referenced aluminum alloy body in the T6 temper” aredefined in Section D, below. In one embodiment, both the first andsecond portions achieve an improvement in strength and elongation ascompared to one or more of (a) the aluminum alloy body in the as-coldworked condition and (b) a reference version of aluminum alloy body inone the T6 temper, such as any of the improved strengthproperties/values listed in the Properties section (Section H), below.

Some embodiments of aluminum alloy bodies, apparatus and methods forproducing tailored amounts of cold work within an aluminum alloy bodieshaving a tailored amount of cold work are illustrated in FIGS. 2 b-21.In one approach, a monolithic aluminum alloy body having non-uniformprofiles prior to the cold working step (200) is used. Examples ofaluminum alloy bodies having a non-uniform profile are illustrated inFIGS. 2 b and 2 c. In FIG. 2 b, the aluminum alloy body 210 b is in theform of a trapezoidal solid (wedge-shaped), having a first height H1associated with a first end 210 b-E1 and a second height H2 associatedwith a second end 210 b-E2, the second height H2 being different thanthe first height H1, in this case being shorter than the first height.An aluminum alloy body having such a profile may be produced viaextruding (or other forming processes), or by machining the aluminumalloy body prior to, or concomitant to, the solutionizing step (140).

Referring now to FIG. 2 d, when an aluminum alloy body is subjected to acold working step (cold rolling via rollers 210 r, in this case), thealuminum alloy body 210 b exits the cold working apparatus 210 r at asingle gauge (e.g., final gauge), but, due to the height differential,the second end 210 b-E2 will receive less cold work than the first end210-E1, and the amount of cold work will vary across the aluminum alloybody 210 b between these two ends 210 b-E1 and 210 b-E2 due to the slopeof the trapezoidal solid. The amount of cold work induced at first end210 b-E1 is at least 25%, and may be any of the cold work levelsdescribed above in Sections (B)(i) or (B)(ii). Thus, after cold working,aluminum alloy body 210 b may have a first level of cold work associatedwith first end 210 b-E1 and a second level of cold work associated withsecond end 210 b-E2, and with the amount of cold work generallyuniformly decreasing between first end 210 b-E1 and second end 210 b-E2.That is, the amount of cold work induced in the aluminum alloy body inthe rolling direction (L direction) will generally uniformly decreasingbetween first end 210 b-E1 and second end 210 b-E2. However, the amountof cold work in the long transverse (LT) direction will generally be thesame for any given LT plane. Such products may be useful as, forexample, automotive panels where high strength is desired in onelocation and high ductility for forming in another, or aerospacestructures such as spars or wing skins where high strength is desired inone location and high damage tolerance in another. For example, a wingskin may have an inboard end (adjacent the fuselage) and an outboardend, with the outboard end receiving more cold work (i.e., associatedwith the first end), and thus having higher strength (possibly withhigher stiffness), and with the inboard end receiving less cold work(i.e., associated with the second end) and thus having improved damagetolerance (toughness and/or fatigue crack growth resistance).

While FIGS. 2 b and 2 d illustrate a situation where the thickness ofthe aluminum alloy body generally uniformly tapers from one end toanother due to a linear slope, non-linear bodies can be used so as toinduce non-uniform cold working. In one embodiment, an aluminum alloybody that is to be rolled comprises at least one curved surface, whichmay be concave or convex, depending on application. When multiple curvedsurfaces are used, multiple different curves will be present, each ofwhich may be concave or convex, depending on application.

In another embodiment, aluminum alloy body 210 b could be rotated about90° such that first end 210 b-E1 and second end 210 b-E2 enter therollers 210 r at about the same time. The amount of cold work induced atfirst end 210 b-E1 is at least 25%, and may be any of the cold worklevels described above in Sections (B)(i) or (B)(ii). However, in thisembodiment, the amount of cold work induced in the aluminum alloy bodyin the transverse direction will generally uniformly decrease betweenfirst end 210 b-E1 and second end 210 b-E2. However, the amount of coldwork in the L direction will generally be the same for any given Ldirection plane. These embodiments may be useful, for example, inproducing wing spars, with a first spar cap having a first property(e.g., higher strength) and a second spar cap having a second property(e.g., lower strength, higher damage tolerance (toughness and/or fatiguecrack growth resistance)), where the first end of the rolled product isassociated with the first spar cap (receives more work) and the secondend of the rolled product is associated with the second spar cap(receives less work).

In another embodiment, and with reference now to FIG. 2 c, an aluminumalloy body 210 c may have a plurality of different profiles 210 p 1-210p 9 prior to the cold working step (200) so as to induce variable coldwork across the aluminum alloy body after the cold working step (200).Specifically, aluminum alloy body 210 c includes a plurality ofgenerally flat profiles 210 p 1, 210 p 3, 210 p 5, 210 p 7, and 210 p 9and a plurality of stepped, tapered profiles 210 p 2, 210 p 4, 210 p 6,210 p 8 separating the plurality of flat profiles. Such profiles may beproduced by, for example, extruding or machining an aluminum alloy bodyprior to the solutionizing step (140).

Referring now to FIG. 2 e, when aluminum alloy body 210 is cold worked(cold rolling via rollers 210 r, in this case), the aluminum alloy body210 c exits the cold working apparatus 210 r at a single uniform gauge(e.g., final gauge, intermediate gauge), but with various sections ofthe aluminum alloy body 210 c having tailored amounts of cold work(210CW1-210CW9). In the illustrated embodiment, rolled aluminum alloybody 210 d receives a first amount of cold work in sections 210CW1 and210CW9, a second amount of cold work in sections 210CW2 and 210CW8, athird amount of cold work in sections 210CW3 and 210CW7, a fourth amountof cold work in sections 210CW4 and 210CW6, and a fifth amount of coldwork in section 210CW5, with the fifth amount of cold work being higherthan the fourth amount of cold work, which is higher than the thirdamount of cold work, which is higher than the second amount of coldwork, which is higher than the first amount of cold work. At least oneof these sections of cold work receives at least 25% cold work. In oneembodiment, at least two of the sections receive at least 25% cold work.In another embodiment, at least three of these sections receive at least25% cold work. In yet another embodiment, at least four of thesesections receive at least 25% cold work. In another embodiment, allsections receive at least 25% cold work. In one embodiment, at least oneof the sections receives no cold work (e.g., is at final gauge beforecold working). While FIG. 2 e illustrates several different sections,the principles of FIG. 2 e may be applied to any aluminum alloy bodyhaving at least two different sections, each section having a differentheight so as to a cold work differential upon rolling.

In one embodiment, the difference in cold work between one section ofthe aluminum alloy body and at least one other section of the aluminumalloy body is at least 10%, i.e., a first section has at least 10% moreor less cold work, as the case may be, than at least one other section.In another embodiment, a first section has at least 15% more or lesscold work, as the case may be, than at least one other section. In yetanother embodiment, a first section has at least 20% more or less coldwork, as the case may be, than at least one other section. In anotherembodiment, a first section has at least 25% more or less cold work, asthe case may be, than at least one other section. In yet anotherembodiment, a first section has at least 30% more or less cold work, asthe case may be, than at least one other section. In another embodiment,a first section has at least 35% more or less cold work, as the case maybe, than at least one other section. In yet another embodiment, a firstsection has at least 40% more or less cold work, as the case may be,than at least one other section. In another embodiment, a first sectionhas at least 45% more or less cold work, as the case may be, than atleast one other section. In yet another embodiment, a first section hasat least 50% more or less cold work, as the case may be, than at leastone other section. In another embodiment, a first section has at least55% more or less cold work, as the case may be, than at least one othersection. In yet another embodiment, a first section has at least 60%more or less cold work, as the case may be, than at least one othersection. In another embodiment, a first section has at least 65% more orless cold work, as the case may be, than at least one other section. Inyet another embodiment, a first section has at least 70% more or lesscold work, as the case may be, than at least one other section. Inanother embodiment, a first section has at least 75% more or less coldwork, as the case may be, than at least one other section. In yetanother embodiment, a first section has at least 80% more or less coldwork, as the case may be, than at least one other section. In anotherembodiment, a first section has at least 85% more or less cold work, asthe case may be, than at least one other section. In yet anotherembodiment, a first section has at least 90% more or less cold work, asthe case may be, than at least one other section. The above-describedtailored cold working differentials apply to any of the tailored coldworking embodiments illustrated in FIGS. 2 b-2 m, and also to any otherembodiments where tailored cold working may be induced.

In the embodiment illustrated in FIG. 2 d, the amount of cold workinduced in the aluminum alloy body in the rolling direction (Ldirection) will vary according to the profiles 210 p 1-210 p 9 andcorresponding cold work sections 210CW1-210CW9. However, the amount ofcold work in the long transverse (LT) direction will generally be thesame for any given LT plane. Such products may be useful as, forexample, a component or part that requires high formability on one end,but high strength on the other, such as stiffeners for aerospacecomponents, buses, trucks, railcars, pressure vessels, and marinecomponents, among others.

In another embodiment, and as illustrated in FIG. 2 f, aluminum alloybody 210 c could be rotated about 90° such that first end 210 c-E1 andsecond end 210 c-E2 enter the rollers 210 r at about the same time. Inthis embodiment, the amount of cold work induced in the aluminum alloybody in the LT direction will vary according to the profiles 210 p 1-210p 9 and corresponding cold work sections 210CW1-210CW9. However, theamount of cold work in the L direction will generally be the same forany given L direction plane. This embodiment might be useful, forexample, as a rocker panel of a door for a car, where high formabilityis required at the ends, but high strength in desired the center, amongothers, and as an automotive pillar (A-pillar, B-pillar, C-pillar), orother body-in-white components.

In another embodiment, and with reference now to FIG. 2 g, an aluminumalloy body 210 g having variable profiles may be cold worked into agenerally uniform gauge final product 210 gfp, such as into acylindrical shape, as illustrated. In this embodiment, the cold workingmay be accomplished by, for example, cold forging steps 210 g-1 and 210g-2. Fewer or more cold forging steps may be employed. Similar to theFIGS. 2 d-2 f, above, the final product 210 gfp may have variablesections of cold work due to the variable profile of the aluminum alloybody prior to the cold working. In the illustrated embodiment, the finalproduct 210 gfp would generally contain a first amount of cold work inthe middle portion (MP) of the cylinder, a second portion of cold worknear the edges (E) of the cylinder, and a generally uniformly decreasingamount of cold work extending from the middle portion (MP) to the edges(E), with at least the middle portion (MP) receiving at least 25% coldwork, such as any of the cold work levels described above in Sections(B)(i) or (B)(ii).

In yet another embodiment, and as illustrated in FIG. 2 h, an aluminumalloy body 210 h having variable profiles may be cold worked into agenerally uniform gauge final product 210 hfp, such as into acylindrical shape, as illustrated. In this embodiment, the cold workingmay be accomplished by, for example, cold forging steps 210 h-1 and 210h-2. Fewer or more cold forging steps may be employed. Similar to theFIGS. 2 d-2 g, above, the final product 210 hfp may have variablesections of cold work due to the variable profile of the aluminum alloybody prior to the cold working. In the illustrated embodiment, the finalproduct 210 hfp would generally contain a first amount of cold work inthe middle portion (MP) of the cylinder, a second portion of cold worknear the edges (E) of the cylinder, and a generally uniformly increasingamount of cold work extending from the middle portion (MP) to the edges(E), with at least the edges (E) receiving at least 25% cold work, suchas any of the cold work levels described above in Sections (B)(i) or(B)(ii).

In another approach, a cold working apparatus is varied to inducevariable cold work in an aluminum alloy body. For example, and withreference now to FIG. 2 i, an intermediate gauge product 210 i may berolled via rollers 210 r, wherein, during the rolling, the rollers aregradually separated so as to produce trapezoidal solid (wedge piece) 210ts having variable cold work in the L direction. Aluminum alloy body 210ts will have variable cold work from a first end to a second end, and,in this case, such variable cold work will generally uniformly taperfrom a first end to a second end, with at least one of the endsreceiving at least 25% cold work, such as any of the cold work levelsdescribed above in Sections (B)(i) or (B)(ii). Rollers 210 r may also benon-uniformly varied to produce any appropriate profiled end product.

In another embodiment, an apparatus may produce a predetermined patternin the aluminum alloy body prior to the solutionizing step (140). Forexample, and with reference now to FIGS. 2 j and 2 m, an aluminum alloybody 211 may be fed to one or more forming/embossing rolls 212, whichmay roll the aluminum alloy body 211 to a first gauge (e.g., anintermediate gauge) and may also produce a plurality of raised portions214 via its indented portions 213. Next the aluminum alloy body may besolutionized 140, after which it may be cold rolled to a second gaugevia cold roller 210 r. The second gauge may be a final gauge, and may bethe same or different than the first gauge. The cold rolled aluminumalloy body 211 cr may thus include a plurality of segregated firstportions 215 having a first amount of cold work, and a plurality ofsecond portions 216 having a second amount of cold work, with at leastsome of the first portions 215 receiving at least 25% cold work, such asany of the cold work levels described above in Sections (B)(i) or(B)(ii). Thus, monolithic aluminum alloy bodies having tailoredthree-dimensional cold working amounts may be produced, and with thefirst portions being deterministically placed in one or more of thelongitudinal direction and the long transverse direction of the rolledproduct (i.e., anywhere in the X-Y coordinate plane, where X relates tothe longitudinal direction and Y relates to the transverse direction).As may be appreciated, any number of rollers can be used to produce theproducts having tailored levels of cold work. Furthermore, while thefeatures have been illustrated relative to the top of the rolledproduct, it will be appreciated that the features may be implemented onthe bottom of the rolled product, or on both the top and bottom of therolled product. Also, each rolling apparatus may include multiple rollstands and/or may use multiple passes to accomplish the rolling.

In the illustrated embodiment, the first portions 215 receive a higheramount of cold work than the second portions 216, and the secondportions 216 generally surround the first portions 215. In oneembodiment, at least some of the first portions receive at least 5% morecold work than the second portions (such as any of the cold workdifferences described above). In one embodiment, the second portionsreceive at least some cold work. In one embodiment, the second portionsalso receive at least 25% cold work. In another embodiment, the secondportions receive little or no cold work (i.e., the first gauge isgenerally equivalent to the second gauge).

In some embodiments, gripping portions 219 may be utilized on thealuminum alloy body so that the body can be forced though one or morerollers, e.g., utilized at the edges of aluminum alloy body, asillustrated in FIG. 2 j. While such gripping portions 219 areillustrated as being on the edges of the aluminum alloy body, they mayalso or alternatively be located in one or more middle portions of thebody, if appropriate, to facilitate movement of the body through therolling apparatus.

In some embodiments, the first portions 215 may each receive generallythe same amount of cold work, such as when indents 213 of roll 212 areof generally the same size so as to produce raised portions 214 ofgenerally the same size. In other embodiments, at least one of the firstportions receives a first amount of cold work and at least another ofthe first portions receives a second amount of cold work, such as whenindents 213 of roll 212 have at least two different sizes, and thusproduce raised portions 214 of different sizes. In these embodiments, atleast some of the first portions receive at least 25% cold work, whileothers of the first portions may receive less then 25% cold work. Theseproducts may be useful, for example, as door panels, where thestrengthened areas are located at, for example, attachment points, butthe non-strengthened areas are located where the aluminum alloy bodyrequires formability.

The first portions 215 may include one or more identifiers. In oneembodiment, the visual identifiers 217 a may be imparted by embossingroll 212, and carried over through the cold rolling operation. Suchidentifier(s) 217 a may be used to identify where the patterns of firstportions 215 are located, so that the material can be separatedappropriately. In other embodiments, the first portions 215 may bevisually identified by embossed markings on the first portionsthemselves. These indicators 217 a can be used, for example, to identifyhigh strength areas, and/or so that the recipient of the material canverify that such areas were, in fact, produced in the material. Inanother embodiment, a visual identifier 217 b may be used to identifywhere to separate the material after the cold working step, such asregistration marks and the like (e.g., to set the start/finish of amaterial blank).

Aside from automotive components, the monolithic bodies produced asshown in FIG. 2 j may be useful, for example, in producing an aerospacecomponent having tailored high strength portions. For example, suchmonolithic bodies may be useful as a wing skin or a fuselage panel. Thehigh strength portions (e.g., first portions) may be used relative toattachment points, or may be located where the stringers, ribs or framesattach to the wing skin or fuselage panel, as appropriate.

In one embodiment, and with continued reference to FIG. 2 j, a pluralityof recessed portions 218 may be imparted into the aluminum alloy body,with these recessed portions 218 being adjacent to one or more raisedportions 214 prior to the cold rolling 210 r. Such recessed portions 218may accommodate the material of the raised portions 214 during the coldworking process. The recessed portions 218 may be imparted, for example,by using an appropriate rolling wheel (e.g., one having at least oneraised surface so as to produce a channel/recessed portion), or bymachining, for example. The recessed portions 218 may be appropriatelyshaped for the cold working process. For example, when a vertical pressdie is used to cold work the material, generally symmetrical recessedportions 218 may be used, with such recessed portions generallysurrounding the raised portions 214. When the aluminum alloy body iscold rolled, non-symmetrical recessed portions 218 may be used toaccommodate flow of the raised portions 214, such as by having recessedportions 218 located adjacent to the back and/or lateral sides of eachof the raised portions 218, among other configurations. Such recessedportions 218 can be appropriately sized and/or shaped to facilitate anappropriate level of residual stress.

In another embodiment, and with reference now to FIG. 2 k, the roller212 may include an indentation 213 that produces an aluminum alloy bodyhaving an extended raised portion 214. In the illustrated embodiment,the raised portion 214 extends the length of the body until it reachesthe cold rollers 210 r. To facilitate production of a uniform gauge,recessed portions 218 (not illustrated) may be located adjacent one side(or both sides) of the extended raised portion 214. This body may besolutionized and, after solutionizing 140, the cold rolling 210 r willflatten and work the raised portion 214, and may produce an aluminumalloy body having a generally uniform gauge (e.g., a final gauge), butwith a first cold worked portion 215 extending the length of the body.One or more second portions 216 may extend adjacent the high cold workportion 215, which second portions may or may not receive cold work. Inthe illustrated embodiment, the first portion 215 extends the length ofthe aluminum alloy body in the L direction, and is surrounded by, and isadjacent to, two second portions 216 that also extend the length of thealuminum alloy body in the L direction. Such aluminum alloy bodies maybe useful, for example, as automotive rocker panels.

As may be appreciated, the embodiment of FIG. 2 k may be reversed (notillustrated), where roller 212 includes two indentations 213 on eitheredge of roller 212, thus producing first portions 215 located on theedges of the rolled product. In this embodiment, a second portion 216separates the first portions 215, and is located in the middle portionof the rolled product. In this embodiment, the first and second portionsmay be of generally similar thickness, but with the edges 215 havinghigh cold work and with the middle 216 having lower or no cold work.Such aluminum alloy bodies may be useful for example, as a componentwhere attachments are made on the edges of the product, and the middleof the product may require, for example, higher ductility. While notshown in FIG. 2 k, the aluminum alloy body may include as many generallyparallel first portions 215 and second portions 214, as appropriate forany particular application.

In another embodiment, and with reference now to FIG. 2 l, a generallyuniform rolled product of intermediate gauge is supplied to cold roller210 r. The cold roller 210 r includes indentation 213, which producessecond portion 216 that extends the length of the body after it exitsthe cold roller 210 r. The cold roller 210 r also produces firstportions 215, with at least one of the first portions having at least25% cold work. The second portion 216 may or may not receive cold work.In the illustrated embodiment, the two first portions 215 extend thelength of the aluminum alloy body in the L direction, and are separatedby a second portion 216 that also extends the length of the aluminumalloy body in the L direction, but has a different (larger) thicknessthan first portions 215. Such aluminum alloy bodies may be useful in,for example, in product applications where extra thickness is requiredto provide stiffness (e.g., aerospace wing skins, rail cars). In anothersimilar embodiment (not illustrated), a cold roller may be of varyingdiameter relative to the LT direction, thus producing a plurality ofportions, each of the portions having a different amount of cold work,but with at least one of the portions receiving at least 25% cold work.While not shown in FIG. 2 l, the aluminum alloy body may include as manygenerally parallel first portions 215 and second portions 214, asappropriate for any particular application.

In another embodiment (not illustrated), a cold working apparatus mayinclude a device that selectively removes only a portion of an aluminumalloy body (e.g., via machining), which may also produce materialssimilar to those illustrated in FIG. 2 l. In one embodiment, the deviceperforates a portion of the aluminum alloy body, e.g., to facilitateremoval of stresses so that the aluminum alloy body does not twist, warpor otherwise distort. In another embodiment, the device removes aportion of the thickness of the aluminum alloy body. In one embodiment,the device separates the produced materials so that the aluminum alloybody does not twist, warp or otherwise distort.

In another embodiment (not illustrated), variable amounts of cold workcan be imparted along the length of tubular products by one or more ofswaging, flow forming, shear forming, cold forging, or cold expansion,to name a few. As described above for rolled products, variable levelsof cold work can be imparted after the solutionizing step and before thethermal treating step or can by imparted prior to the solutionizingstep, in which case machining may also be used to create the initialgeometry. In this case, the cold working step can provide an aluminumalloy product that is either uniform in final cross section or havingvariable final geometry. Such methods might be useful, for example, increating pipes or tubes with different properties in one or both endscompared to the central sections. In one embodiment, a monolithicaluminum alloy tubular product is provided, the tubular product having afirst portion and a second portion adjacent the first portion, whereinthe first portion comprises at least 25% cold work, and wherein secondportion has at least 5% less cold work as compared to the first portion,such as any of the above-described cold work differentials. In oneembodiment, the monolithic aluminum alloy tubular product has a uniforminner diameter. In one embodiment, the monolithic aluminum alloy tubularproduct has a uniform outer diameter. In one embodiment, the monolithicaluminum alloy tubular product has a uniform inner and outer diameter.

While the features of FIGS. 2 b-2 m have generally been describedrelative to cold rolling and/or cold forging, other cold workingmechanisms may also be employed to produce aluminum alloy bodies havingtailored cold work. Furthermore, aluminum alloy bodies having variableprofiles can be produced in a variety of known manners, including thosedescribed above, and also via extruding, forging, and machining, amongothers. Such profiled aluminum alloy bodies can then be cold worked inany of the above described manners to produce aluminum alloy bodieshaving tailored cold work.

iv. Cold Working Temperature

The cold working step (200) may be initiated at temperatures below hotworking temperatures (e.g., not greater than 400° F.). In one approach,the cold working step (200) is initiated when the aluminum alloy bodyreaches a sufficiently low temperature after solutionizing (140). In oneembodiment, the cold working step (200) may be initiated when thetemperature of the aluminum alloy body is not greater than 250° F. Inother embodiments, the cold working step (200) may be initiated when thetemperature of the aluminum alloy body is not greater than 200° F., ornot greater than 175° F., or not greater than 150° F., or not greaterthan 125° F., or less. In one embodiment, a cold working step (200) maybe initiated when the temperature of the aluminum alloy body is aroundambient. In other embodiments, a cold working step (200) may beinitiated at higher temperatures, such as when the temperature of thealuminum alloy body is in the range of from 250° F. to less than hotworking temperatures (e.g., less than 400° F.).

In one embodiment, the cold working step (200) is initiated and/orcompleted in the absence of any purposeful/meaningful heating (e.g.,purposeful heating that produces a material change in the microstructureand/or properties of the aluminum alloy body). Those skilled in the artappreciate that an aluminum alloy body may realize an increase intemperature due to the cold working step (200), but that such coldworking steps (200) are still considered cold working (200) because theworking operation began at temperatures below those considered to be hotworking temperatures. When a plurality of cold working operations areused to complete the cold working step (200), each one of theseoperations may employ any of the above-described temperature(s), whichmay be the same as or different from the temperatures employed by aprior or later cold working operation.

As noted above, the cold working (200) is generally initiated when thealuminum alloy body reaches a sufficiently low temperature aftersolutionizing (140). Generally, no purposeful/meaningful thermaltreatments are applied to the aluminum alloy body between the end of thesolutionizing step (140) and the beginning of the cold working step(200), i.e., the process may be absent of thermal treatments between thecompletion of the solutionizing step (140) and the initiation of thecold working step (200). In some instances, the cold working step (200)is initiated soon after the end of the solutionizing step (140) (e.g.,to facilitate cold working). In one embodiment, the cold working step(200) is initiated not more than 72 hours after the completion of thesolutionizing step (140). In other embodiments, the cold working step(200) is initiated in not greater than 60 hours, or not greater than 48hours, or not greater than 36 hours, or not greater than 24 hours, ornot greater than 20 hours, or not greater than 16 hours, or not greaterthan 12 hours, or less, after the completion of the solutionizing step(140). In one embodiment, the cold working step (200) is initiatedwithin a few minutes, or less, of completion of the solutionizing step(140) (e.g., for continuous casting processes). In another embodiment,the cold working step (200) is initiated concomitant to completion ofthe solutionizing step (140) (e.g., for continuous casting processes).

In other instances, it may be sufficient to begin the cold working (200)after a longer elapse of time relative to the completion of thesolutionizing step (140). In these instances, the cold working step(200) may be completed one or more weeks or months after the completionof the solutionizing step (140).

C. Thermally Treating

Referring still to FIG. 2 a, a thermally treating step (300) iscompleted after the cold working step (200). “Thermally treating” andthe like means purposeful heating of an aluminum alloy body such thatthe aluminum alloy body reaches an elevated temperature. The thermaltreatment step (300) may include heating the aluminum alloy body for atime and at a temperature sufficient to achieve a condition or property(e.g., a selected strength, a selected ductility, among others).

After solutionizing, most heat treatable alloys, such as Al—Li alloys,exhibit property changes at room temperature. This is called “naturalaging” and may start immediately after solutionizing, or after anincubation period. The rate of property changes during natural agingvaries from one alloy to another over a wide range, so that the approachto a stable condition may require only a few days or several years.Since natural aging occurs in the absence of purposeful heating, naturalaging is not a thermal treatment step (300). However, natural aging mayoccur before and/or after the thermal treatment step (300). Naturalaging may occur for a predetermined period of time prior to the thermaltreatment step (300) (e.g., from a few minutes or hours to a few weeks,or more). Natural aging may occur between or after any of thesolutionizing (140), the cold working (200) and the thermal treatmentsteps (300).

The thermally treating step (300) heats the aluminum alloy body to atemperature within a selected temperature range. For the purposes of thethermally treating step (300), this temperature refers to the averagetemperature of the aluminum alloy body during the thermally treatingstep (300). The thermally treating step (300) may include a plurality oftreatment steps, such as treating at a first temperature for a firstperiod of time, and treating at a second temperature for a second periodof time. The first temperature may be higher or lower than the secondtemperature, and the first period of time may be shorter or longer thanthe second period of time.

The thermally treating step (300) is generally completed such that thealuminum alloy body achieves/maintains a predominately unrecrystallizedmicrostructure, as defined below. As described in further detail below,a predominately unrecrystallized microstructure may achieve improvedproperties. In this regard, the thermally treating step (300) generallycomprises heating the aluminum alloy body to an elevated temperature,but below the recrystallization temperature of the aluminum alloy body,i.e., the temperature at which the aluminum alloy body would not achievea predominately unrecrystallized microstructure. For example, thethermally treating step (300) may comprise heating the Al—Li alloy bodyto a temperature in the range of from 150° F. to 425° F. (or higher),but below the recrystallization temperature of the aluminum alloy body.When thermally treating, especially in excess of 425° F., it may benecessary to limit the exposure period so that the produced aluminumalloy body realizes improved properties. As may be appreciated, whenhigher thermal treatment temperatures are used, shorter thermal exposureperiods may be required to realize the predominately unrecrystallizedmicrostructure and/or other desired properties (e.g., absence of unduesoftening due to removal of dislocations from high temperatureexposure).

The thermally treating step (300) may be completed in any suitablemanner that maintains the aluminum alloy body at one or more selectedtemperature(s) for one or more selected period(s) of time (e.g., inorder to achieve a desired/selected property or combination ofproperties). In one embodiment, the thermally treating step (300) iscompleted in an aging furnace, or the like. In another embodiment, thethermally treating step (300) is completed during a paint-bake cycle.Paint-bake cycles are used in the automotive and other industries tocure an applied paint by baking it for a short period of time (e.g.,5-30 minutes). Given the ability for the presently described processesto produce aluminum alloy bodies having high strength within a shortperiod of time, as described below, paint-bake cycles, and the like, maybe used to complete the thermally treating step (300), thereby obviatingthe need for separate thermal treatment and paint-bake steps. Similarly,in another embodiment, the thermally treating step (300) may becompleted during a coating cure step, or the like.

In one embodiment, a method comprises (i) receiving a solutionizedaluminum alloy body, and (ii) then cold working the aluminum alloy body,and (iii) then thermally treating the aluminum alloy body, wherein thecold working and the thermally treating steps are accomplished toachieve an improved property as compared to one or more of (a) thealuminum alloy body in the as-cold worked condition and (b) a referenceversion of the aluminum alloy body in the T6 temper, such as achievementof any of the properties listed in the Properties section (Section H),above. Such a method may be applicable to, and thus employed with, anyof the aluminum alloy products described in the Product Applicationssection (Section I), below.

In another embodiment, a method comprises (i) receiving an aluminumalloy body that has been solutionized and then cold worked by at least25%, and (ii) then thermally treating the aluminum alloy body, whereinthe cold working and the thermally treating steps are accomplished toachieve an improved property as compared to one or more of (a) thealuminum alloy body in the as-cold worked condition and (b) a referenceversion of the aluminum alloy body in the T6 temper, such as achievementof any of the properties listed in the Properties section (Section H),above. Such a method may be applicable to, and thus employed with, anyof the aluminum alloy products described in the Product Applicationssection (Section I), below.

i. Completion of Cold Working and/or Thermally Treating Step(s) toAchieve One or More Preselected Precursor Conditions

In one approach, an aluminum alloys body is processed such that itachieves a preselected precursor condition during at least one of thecold working step (200) and the thermally treating step (300). Apreselected precursor condition is a condition that is selected inadvance of production of the aluminum alloy body, and is a precursor toanother condition (usually another known condition, such as a desiredend condition or property of an aluminum alloy product). For example,and as explained in further detail below, an aluminum alloy supplier,having completed cold working step (200), may supply an aluminum alloybody (e.g., a sheet) in a preselected underaged condition by subjectingthe body to a preselected heating practice as part of the thermaltreatment step (300). A customer of the aluminum alloy supplier mayreceive this aluminum alloy body, and may further thermally process thisaluminum alloy body, such as by warm forming the body into apredetermined shaped product, thereby completing the remaining portionof the thermal treatment step (300), and, in the process, furtherincreasing the strength of the aluminum alloy body. Thus, an aluminumalloy supplier may tailor their first heating step such that thecombination of their first heating step and the customer's later secondheating step produce an aluminum alloy body having predeterminedproperties (e.g., near peak strength, a predetermined combination ofstrength and ductility, among others). Many other variations exist, manyof which are explained in further detail below.

A. Multiple Thermal Treatment Steps

In one embodiment, and with reference now to FIG. 2 q-1, a thermallytreating step (300) includes a first heating step (320) and a secondheating step (340). The first heating step (320) may be conducted toachieve a preselected condition (322) (e.g., a first selectedcondition). Similarly, the second heating step (340) may be conducted toachieve another preselected condition (342) (e.g., a second selectedcondition).

Referring now to FIG. 2 q-2, the first selected condition (322) may beselected, for example, to achieve a predetermined strength, apredetermined elongation, or a predetermined combination of strength andelongation, among other properties (330). Thus, the selected condition(322) may be a predetermined underaged condition (324), a peaked agedcondition (326), or a predetermined overaged condition (328). In oneembodiment, the first heating step (320) is conducted for a firstselected time and a first selected temperature to achieve the firstselected condition (322).

Similarly, and referring now to FIG. 2 q-3, the second heating step(340) may be selected to achieve a predetermined strength, apredetermined elongation, or a predetermined combination of strength andelongation, among other properties (350). Thus, the second heating step(340) may be conducted to achieve a second selected condition (342),such as any of a predetermined underaged condition (344), a peak agecondition (346), or a predetermined overage condition (348). In someembodiments, the second heating step (340) is conducted for a secondselected time and a second selected temperature to achieve the secondselected condition (342).

Given that the first heating step (320) may be tailored to achieve oneor more preselected conditions, tailored aluminum alloy bodies may beproduced in the first heating step (320) and at a first location forsubsequent processing via the second heating step (340). For example, analuminum alloy supplier may conduct a first heating step at a firstlocation to achieve the selected condition (322). The aluminum alloysupplier may then provide such aluminum alloy body to a customer (orother entity), who may subsequently conduct the second heating step(340) at a second location remote of the first location (e.g., toachieve the second selected condition (342)). Thus, tailored aluminumalloy bodies having predetermined properties may be achieved.

By way of example, and with reference now to FIG. 2 q-4, a first heatingstep (320) may achieve a predetermined underaged condition (324). Thispredetermined underaged condition may be within a predetermined amountof a peak strength of the aluminum alloy body, such as within apredetermined amount of an ultimate tensile strength and/or a tensileyield strength of the aluminum alloy body. In one embodiment, thepredetermined underaged condition (324) is within 30% of a peak strengthof the aluminum alloy body. In other embodiments, the predeterminedunderaged condition (324) is within 20%, or within 10%, or within 5%, orless, of a peak strength of the aluminum alloy body. In one embodiment,the predetermined underaged condition (324) is within 20 ksi of a peakstrength of the aluminum alloy body. In other embodiments, thepredetermined underaged condition (324) is within 15 ksi, or within 10ksi, or within 5 ksi, or less, of a peak strength of the aluminum alloybody. Thus, the aluminum alloy body, having been subjected to the firstheating step (320), may be supplied from a supplier to a customer, andin the predetermined underaged condition (324). In turn, the secondheating step (340) may be completed by the customer to achieve apredetermined higher strength condition (372) relative to the priorpredetermined underaged condition (324). This predetermined higherstrength condition (372) may be within a predetermined amount of a peakstrength of the aluminum alloy body, such as a peak ultimate tensilestrength and/or a peak tensile yield strength of the aluminum alloybody. In one embodiment, the predetermined higher strength condition(372) is within 15% of a peak strength of the aluminum alloy body. Inother embodiments, the predetermined higher strength condition (372) iswithin 10%, or within 8%, or within 6%, or within 4%, or within 2%, orwithin 1%, or less, of a peak strength of the aluminum alloy body.Similarly, the predetermined higher strength condition (372) may bewithin 15 ksi of a peak strength of the aluminum alloy body. In otherembodiments, the predetermined higher strength condition (372) may bewithin 10 ksi, or within 8 ksi, or within 6 ksi, or within 4 ksi, orwithin 2 ksi, or within 1 ksi, or less, of a peak strength condition ofthe aluminum alloy body.

By way of illustration, a customer upon receipt of an aluminum alloybody that was subjected to a preparing step (100), a cold working step(200), and the first heating step (320), and thus being in apredetermined underaged condition (324), may subsequently conduct thesecond heating step (340) to achieve the second predetermined higherstrength condition (372). For example, and with reference now to FIG. 2q-5, the second heating step (340) may be one or more of a warm formingprocess, a paint bake process, a drying process, and/or a tailored agingprocess conducted in an aging furnace, among others. Such second heatingstep (340) processes may be conducted in any order as appropriate to thespecific aluminum alloy body and its corresponding final form.

In one non-limiting example, and as described in further detail below,an aluminum alloy sheet may be supplied to an automotive manufacturerafter completing the first heating step (320). Thus, the automotivesupplier may receive the aluminum alloy sheet in a predeterminedselected condition (322) for later processing. The automotivemanufacturer may then form this part into a predetermined shaped productduring at least a part of the second heating step (340) (“warm forming”,which is defined in Section F, below). After the warm forming step, anautomotive manufacturer may paint bake and/or dry this predeterminedshaped product, thereby subjecting the aluminum alloy body to additionalthermal treatments as part of the second heating step (340) to achieve asecond selected condition (342). Similarly, the automotive manufacturermay subject the predetermined shaped product to an aging furnace, or thelike, before or after any of the other heating operations to tailorproperties of the predetermined shaped product.

Given that, for any alloy, a peak strength will be known based on agingcurves, the automotive manufacturer may be able to receive aluminumalloy bodies in a first selected condition (322), so that the automotivemanufacturer's subsequent thermal processing achieves a second selectedcondition, such as a higher strength condition. In some embodiments, theautomotive manufacturer may conduct a second heating step (340) so as tofacilitate achievement of a peak strength or near peak strengthcondition (346), as described above. In other embodiments, theautomotive manufacturer may select a predetermined overaged (348) and/orunderaged condition (344) to achieve a predetermined set of properties(350). For example, in an overaged condition (348), an automotivemanufacturer may achieve higher ductility at slightly lower strengthrelative to a peak strength condition, thus facilitating a different setof properties relative to a peak strength condition (346). Similarly,underaged properties (344) may provide a different set of mechanicalproperties that may be useful to an automotive manufacturer. Thus,tailored aluminum alloy bodies having predetermined properties may beachieved, such as any of the properties described in the Propertiessection (Section H), below.

Referring now to FIG. 2 q-6, one specific embodiment of a thermaltreatment practice is illustrated. In this embodiment, the aluminumalloy body may be supplied to a customer in either the as-cold workedcondition or the T3 temper (i.e., the customer may receive the aluminumalloy after the cold working step (200), and without any thermaltreatments being applied by the aluminum alloy supplier). In thisembodiment, the customer may complete the thermal treatment step (300)and the optional final treatment step (400). As shown in the illustratedembodiment, the optional final treatment may include the forming of thepredetermined shaped product (500) during the thermally treating step(300). That is to say, the customer completes all the thermal treatmentsteps, which may include a warm forming step (320′). Other oralternative thermal treatments may be employed by the customer, such asany of those illustrated in FIG. 2 q-5, among others.

Referring back to FIG. 2 q-1, since the first heating step (320) may beconducted at a first location, and the second heating step (340) may beconducted at a second location, the steps prior to the first heatingstep (320) may also be completed at the first location. That is, thepreparing the aluminum alloy body for post-solutionizing cold work step(100) may be completed at the first location and/or the cold working thealuminum alloy body step (200) may be completed at the first location.However, such processing steps are not required to be completed at thefirst location. Similarly, it is possible that all of the steps could becompleted at a single location. Furthermore, while the above examplesare explained relative to automotive products, such methodologies areapplicable to many aluminum applications, such as any of the productsdescribed in the Product Applications section (Section I), below.

Also, while FIGS. 2 q-1 to 2 q-5 have been described relative toachieving two preselected conditions (322), (342), it is not requiredthat two selected conditions be employed. For example, an aluminumsupplier may employ a first selected condition (322) based uponknowledge of a customer's processes to facilitate improvement of thecustomer's aluminum alloy products, and without the customer defining asecond selected condition. Thus, in some embodiments, only a singlepreselected condition is employed (e.g., selected condition (322)).Furthermore, as described above relative to FIG. 2 a, when the thermallytreating step (300) is completed at a single location, it may include aplurality of treatment steps, such as treating at a first temperaturefor a first period of time, and treating at a second temperature for asecond period of time, and this first temperature may be higher or lowerthan the second temperature, and the first period of time may be shorteror longer than the second period of time. Similarly, each of heatingsteps (320) and (340) may also include a plurality of treatment steps,such as treating at a first temperature for a first period of time, andtreating at a second temperature for a second period of time, and thisfirst temperature may be higher or lower than the second temperature,and the first period of time may be shorter or longer than the secondperiod of time. Furthermore, while only two separate heating steps(320), (340) have been illustrated and described, it will be appreciatedthat any number of separate heating steps may be employed and at anysuitable number of locations to achieve the thermally treating step(300), and that a preselected condition/property may be used withrespect to one or more of these separate heating steps.

B. Multiple Cold Working Steps

Similar to the multiple thermal treatment step embodiments describedabove, multiple cold working steps may also be employed. In oneembodiment, and with reference now to FIG. 2 q-7, a cold working step(200) includes a first cold working step (220) and a second cold workingstep (240), with the combination of the first cold working step (220)and second cold working step (240) inducing at least 25% cold work inthe aluminum alloy body. In one embodiment, the first cold working step,in of itself, induces at least 25% cold work in the aluminum alloy body.Thus, the first cold working step (220) may be conducted to achieve apreselected condition (222) (e.g., a first selected condition).Similarly, the second cold working step (240) may be conducted toachieve another preselected condition (242) (e.g., a second selectedcondition).

Referring now to FIG. 2 q-8, the first selected condition (222) may beselected, for example, to achieve a predetermined strength, apredetermined elongation, or a predetermined combination of strength andelongation, among other properties (230). Similarly, the second selectedcondition (232) may be selected, for example, to achieve a predeterminedstrength, a predetermined elongation, or a predetermined combination ofstrength and elongation, among other properties (250).

Given that the first cold working step (220) may be tailored to achieveone or more preselected conditions, tailored aluminum alloy bodies maybe produced in the first cold working step (220) and at a first locationfor subsequent processing via the second cold working step (240) andthermal treatment step (300). For example, an aluminum alloy suppliermay conduct a first cold working step at a first location to achieve theselected condition (222). The aluminum alloy supplier may then providesuch aluminum alloy body to a customer (or other entity), who maysubsequently conduct the second cold working step (240) and thethermally treating step (300) at a second location (or more locations)remote of the first location (e.g., to achieve the second selectedcondition (342)). Thus, tailored aluminum alloy bodies havingpredetermined properties may be achieved, such as any of the propertiesdescribed in the Properties section (Section H), below.

While FIGS. 2 q-7 to 2 q-8 have been described relative to achieving twopreselected conditions (222), (242), it is not required that twoselected conditions be employed. For example, an aluminum supplier mayemploy a first selected condition (222) based upon knowledge of acustomer's processes to facilitate improvement of the customer'saluminum alloy products, and without the customer defining a secondselected condition. Thus, in some embodiments, only a single preselectedcondition is employed (e.g., selected condition (222)). Furthermore,while only two cold working steps (220), (240) have been illustrated anddescribed, it will be appreciated that any number of separate coldworking steps may be employed and at any suitable number of locations toachieve the cold working step (200), and a preselectedcondition/property may be used with respect to one or more of theseseparate cold working steps.

C. Cold Working and Thermally Treating Multiple Times at DifferentLocations

In another embodiment, a first cold working step and a first thermaltreatment step may be completed at a first location, and a second coldworking step and a second thermal treatment step may be completed at asecond location to achieve one or more predetermined properties. Forexample, and with reference now to FIG. 2 q-9, to complete the coldworking step (200) and the thermal treatment step (300), a first coldworking step (220) and a first thermal treatment step (320) may becompleted at a first location, and a second cold working step (240) anda second thermal treatment step (340) may be completed at a secondlocation, with the combination of the first cold working step (220) andsecond cold working step (240) inducing at least 25% cold work in thealuminum alloy body. In one embodiment, the first cold working step, inof itself, induces at least 25% cold work in the aluminum alloy body.

By way of illustration, and with reference now to FIGS. 2 q-1, 2 q-2,and 2 q-9, an aluminum alloy supplier may complete the first coldworking step (220) and the first heating step (320), e.g., to achieve apreselected condition (322), such as a predetermined strength, apredetermined elongation, or a predetermined combination of strength andelongation (330), among others. A customer may receive the aluminumalloy body that was prepared for post-solutionizing cold work (100),first cold worked (220), and first heated (320). The customer may thencomplete the second cold working step (240) and the second thermallytreating step (340) to complete the cold working step (200) andthermally treating step (300), optionally with final treatments (400),and optionally to achieve another preselected condition (242) (e.g., asecond selected condition). Thus, tailored aluminum alloy bodies havingpredetermined properties may be achieved, such as any of the propertiesdescribed in the Properties section (Section H), below. Theseembodiments may be useful, for example, in automotive, aerospace andcontainer applications, among others.

While FIG. 2 q-9 has been described relative to achieving twopreselected conditions (322), (342), it is not required that twoselected conditions be employed. For example, an aluminum supplier mayemploy a first selected condition (322) based upon knowledge of acustomer's processes to facilitate improvement of the customer'saluminum alloy products, and without the customer defining a secondselected condition. Thus, in some embodiments, only a single preselectedcondition is employed (e.g., selected condition (322)). Furthermore,while only two cold working steps (220), (240) and two heating steps(320), (340) have been illustrated and described, it will be appreciatedthat any number of separate cold working steps may be used to accomplishthe cold working step (200) at any number of suitable locations, and anynumber of separate heating steps may be employed to accomplish thethermally treating step (300) and at any suitable number of locations,and a preselected condition/property may be used with respect to one ormore of these separate cold working and/or separate heating steps.

D. Cold Working and Thermally-Treating Combination

The combination of the cold working step (200) and the thermallytreating step (300) are capable of producing aluminum alloy bodieshaving improved properties. It is believed that the combination of thehigh deformation of the cold working step (200) in combination with theappropriate thermally treatment conditions (300) produce a uniquemicrostructure (see, Microstructure, below) capable of achievingcombinations of strength and ductility that have been heretoforeunrealized. The cold working step (200) facilitates production of aseverely deformed microstructure while the thermally treating step (300)facilitates precipitation hardening. When the cold working (200) is atleast 25%, and preferably more than 50%, and when an appropriate thermaltreatment step (300) is applied, improved properties may be realized.

In one approach, the cold working (200) and thermally treating (300)steps are accomplished such that the aluminum alloy body achieves anincrease in strength (e.g., tensile yield strength (R_(0.2)) or ultimatetensile strength (R_(m))). The strength increase may be realized in oneor more of the L, LT or ST directions. “Accomplished such that”,“accomplished to achieve”, and the like, means that the referencedproperty or properties are determined after the referenced step or stepsare concluded (e.g., properties are not measured in the middle of athermally treating step, but are instead measured upon conclusion of thethermally treating step).

In one embodiment, the cold working (200) and thermally treating (300)steps are accomplished such that the aluminum alloy body achieves anincrease in strength as compared to a reference-version of the aluminumalloy body in the “as-cold worked condition”. In another embodiment, thecold working (200) and thermally treating (300) steps are accomplishedsuch that the aluminum alloy body achieves an increase in strength ascompared to a reference-version of the aluminum alloy body in the T6temper. In yet another embodiment, the cold working (200) and thermallytreating (300) steps are accomplished such that the aluminum alloy bodyachieves an increase in strength as compared to a reference-version ofthe aluminum alloy body in the T87 temper. In another embodiment, thecold working (200) and thermally treating (300) steps are accomplishedsuch that the aluminum alloy body achieves an increase a higher R-valueas compared to a reference-version of the aluminum alloy body in the T4temper. These and other properties are described in the Propertiessection, below.

The “as-cold worked condition” (ACWC) means: (i) the aluminum alloy bodyis prepared for post-solutionizing cold work, (ii) the aluminum alloybody is cold worked, (iii) not greater than 4 hours elapse between thecompletion of the solutionizing step (140) and the initiation of thecold working step (200), and (iv) the aluminum alloy body is notthermally treated. The mechanical properties of the aluminum alloy bodyin the as-cold worked condition should be measured within 4-14 days ofcompletion of the cold working step (200). To produce areference-version of the aluminum alloy body in the “as-cold workedcondition”, one would generally prepare an aluminum alloy body forpost-solutionizing cold work (100), and then cold work the aluminumalloy body (200) according to the practices described herein, afterwhich a portion of the aluminum alloy body is removed to determine itsproperties in the as-cold worked condition per the requirementsdescribed above. Another portion of the aluminum alloy body would beprocessed in accordance with the new processes described herein, afterwhich its properties would be measured, thus facilitating a comparisonbetween the properties of the reference-version of the aluminum alloybody in the as-cold worked condition and the properties of an aluminumalloy body processed in accordance with the new processes describedherein (e.g., to compare strength, ductility, fracture toughness). Sincethe reference-version of the aluminum alloy body is produced from aportion of the aluminum alloy body, it would have the same compositionas the aluminum alloy body.

The “T6 temper” and the like means an aluminum alloy body that has beensolutionized and then thermally treated to a maximum strength condition(within 1 ksi of peak strength); applies to bodies that are not coldworked after solutionizing, or in which the effect of cold work inflattening or straightening may not be recognized in mechanical propertylimits. As described in further detail below, aluminum alloy bodiesproduced in accordance with the new processes described herein mayachieve superior properties as compared to the aluminum alloy body in aT6 temper. To produce a reference-version of the aluminum alloy body ina T6 temper, one would prepare an aluminum alloy body forpost-solutionizing cold work (100), after which a portion of thealuminum alloy body would be processed to a T6 temper (i.e., areferenced aluminum alloy body in the T6 temper). Another portion of thealuminum alloy body would be processed in accordance with the newprocesses described herein, thus facilitating a comparison between theproperties of the reference-version of the aluminum alloy body in the T6temper and the properties of an aluminum alloy body processed inaccordance with the new processes described herein (e.g., to comparestrength, ductility, fracture toughness). Since the reference-version ofthe aluminum alloy body is produced from a portion of the aluminum alloybody, it would have the same composition as the aluminum alloy body. Thereference-version of the aluminum alloy body may require work (hotand/or cold) before the solutionizing step (140) to place thereference-version of the aluminum alloy body in a comparable productform to the new aluminum alloy body (e.g., to achieve the same finalthickness for rolled products)

The “T4 temper” and the like means an aluminum alloy body that has beensolutionized and then naturally aged to a substantially stablecondition; applies to bodies that are not cold worked aftersolutionizing, or in which the effect of cold work in flattening orstraightening may not be recognized in mechanical property limits. Toproduce a reference-version of the aluminum alloy body in a T4 temper,one would prepare an aluminum alloy body for post-solutionizing coldwork (100), after which a portion of the aluminum alloy body would beallowed to naturally age to a T4 temper (i.e., a referenced aluminumalloy body in the T4 temper). Another portion of the aluminum alloy bodywould be processed in accordance with the new processes describedherein, thus facilitating a comparison between the properties of thereference-version of the aluminum alloy body in the T4 temper and theproperties of an aluminum alloy body processed in accordance with thenew processes described herein (e.g., to compare strength, ductility,fracture toughness). Since the reference-version of the aluminum alloybody is produced from a portion of the aluminum alloy body, it wouldhave the same composition as the aluminum alloy body. Thereference-version of the aluminum alloy body may require work (hotand/or cold) before the solutionizing step (140) to place thereference-version of the aluminum alloy body in a comparable productform to the new aluminum alloy body (e.g., to achieve the same thicknessfor rolled products).

The “T87 temper” and the like means an aluminum alloy body that has beensolutionized, cold worked 10% (rolled or stretched), and then thermallytreated to a maximum strength condition (within 1 ksi of peak strength).As described in further detail below, aluminum alloy bodies produced inaccordance with the new processes described herein may achieve superiorproperties over a comparable aluminum alloy body in a T87 temper. Toproduce a reference-version of the aluminum alloy body in a T87 temper,one would prepare an aluminum alloy body for post-solutionizing coldwork (100), after which a portion of the aluminum alloy body would beprocessed to a T87 temper (i.e., a referenced aluminum alloy body in theT87 temper). Another portion of the aluminum alloy body would beprocessed in accordance with the new processes described herein, thusfacilitating a comparison between the properties of thereference-version of the aluminum alloy body in the T87 temper and theproperties of an aluminum alloy body processed in accordance with thenew processes described herein (e.g., to compare strength, ductility,fracture toughness). Since the reference-version of the aluminum alloybody is produced from a portion of the aluminum alloy body, it wouldhave the same composition as the aluminum alloy body. Thereference-version of the aluminum alloy body may require work (hotand/or cold) before the solutionizing step (140) to place thereference-version of the aluminum alloy body in a comparable productform to the new aluminum alloy body (e.g., to achieve the same thicknessfor rolled products).

The “T3 temper” and the like means an aluminum alloy body that has beensolutionized, cold worked and then naturally aged (i.e., no thermaltreatment has been applied at the time properties are measured). Toproduce a reference-version of the aluminum alloy body in a T3 temper,one would prepare an aluminum alloy body for post-solutionizing coldwork (100), after which the aluminum alloy body is naturally aged (roomtemperature aged) until the strength stabilizes, usually after a fewdays or weeks. Another portion of the aluminum alloy body would be thenthermally treated in accordance with the new processes described herein,thus facilitating a comparison between the properties of thereference-version of the aluminum alloy body in the T3 temper and theproperties of an aluminum alloy body processed in accordance with thenew processes described herein (e.g., to compare strength, ductility,fracture toughness). Since the reference-version of the aluminum alloybody is produced from a portion of the aluminum alloy body, it wouldhave the same composition as the aluminum alloy body.

In one embodiment, the cold working step is initiated at a temperatureof not greater than 400° (e.g., at a temperature of not greater than250° F.) and the thermally treating step (300) is conducted at atemperature of at least 150° F. In these embodiments, the thermallytreating step (300) and cold working step (200) may overlap (partiallyor fully) so long as they are conducted such that the new aluminum alloybodies described herein are produced. In these embodiment, the thermallytreating step (300) may be completed concomitant to the cold workingstep (200).

E. Microstructure

i. Recrystallization

The cold working (200) and thermally treating (300) steps may beaccomplished such that the aluminum alloy body achieves/maintains apredominately unrecrystallized microstructure. A predominatelyunrecrystallized microstructure means that the aluminum alloy bodycontains less than 50% of first type grains (by volume fraction), asdefined below.

An aluminum alloy body has a crystalline microstructure. A “crystallinemicrostructure” is the structure of a polycrystalline material. Acrystalline microstructure has crystals, referred to herein as grains.“Grains” are crystals of a polycrystalline material.

“First type grains” means those grains of a crystalline microstructurethat meet the “first grain criteria”, defined below, and as measuredusing the OIM (Orientation Imaging Microscopy) sampling procedure,described below. Due to the unique microstructure of the aluminum alloybody, the present application is not using the traditional terms“recrystallized grains” or “unrecrystallized grains”, which can beambiguous and the subject of debate, in certain circumstances. Instead,the terms “first type grains” and “second type grains” are being usedwhere the amount of these types of grains is accurately and preciselydetermined by the use of computerized methods detailed in the OIMsampling procedure. Thus, the term “first type grains” includes anygrains that meet the first grain criteria, and irrespective of whetherthose skilled in the art would consider such grains to beunrecrystallized or recrystallized.

The OIM analysis is to be completed from the T/4 (quarter-plane)location to surface of the L-ST plane. The size of the sample to beanalyzed will generally vary by gauge. Prior to measurement, the OIMsamples are prepared by standard metallographic sample preparationmethods. For example, the OIM samples are generally polished withBuehler Si—C paper by hand for 3 minutes, followed by polishing by handwith a Buehler diamond liquid polish having an average particle size ofabout 3 microns. The samples are anodized in an aqueous fluoric-boricsolution for 30-45 seconds. The samples are then stripped using anaqueous phosphoric acid solution containing chromium trioxide, and thenrinsed and dried.

The “OIM sample procedure” is as follows:

-   -   The software used is TexSEM Lab OIM Data Collection Software        version 5.31 (EDAX Inc., New Jersey, U.S.A.), which is connected        via FIREWIRE (Apple, Inc., California, U.S.A.) to a DigiView        1612 CCD camera (TSL/EDAX, Utah, U.S.A.). The SEM is a JEOL        JSM6510 (JEOL Ltd. Tokyo, Japan).    -   OIM run conditions are 70° tilt with a 18 mm working distance        and an accelerating voltage of 20 kV with dynamic focusing and        spot size of 1 times 10⁻⁷ amp. The mode of collection is a        square grid. A selection is made such that orientations are        collected in the analysis (i.e., Hough peaks information is not        collected). The area size per scan (i.e., the frame) is 2.0 mm        by 0.5 mm for 2 mm gauge samples and 2.0 mm by 1.2 mm for 5 mm        gauge samples at 3 micron steps at 80×. Different frame sizes        can be used depending upon gauge. The collected data is output        in an *.osc file. This data may be used to calculate the volume        fraction of first type grains, as described below.    -   Calculation of volume fraction of first type grains: The volume        fraction of first type grains is calculated using the data of        the *.osc file and the TexSEM Lab OIM Analysis Software version        5.31. Prior to calculation, data cleanup may be performed with a        15° tolerance angle, a minimum grain size=3 data points, and a        single iteration cleanup. Then, the amount of first type grains        is calculated by the software using the first grain criteria        (below).    -   First grain criteria: Calculated via grain orientation spread        (GOS) with a grain tolerance angle of 5°, minimum grain size is        three (3) data points, and confidence index is zero (0). All of        “apply partition before calculation”, “include edge grains”, and        “ignore twin boundary definitions” should be required, and the        calculation should be completed using “grain average        orientation”. Any grain whose GOS is ≦3° is a first type grain.        If multiple frames are used, the GOS data are averaged.

“First grain volume” (FGV) means the volume of first type grains of thecrystalline material.

“Percent Unrecrystallized” and the like is determined via the formula:

U _(RX)%=(1−FGV)*100%

As mentioned above, the aluminum alloy body generally comprises apredominately unrecrystallized microstructure, i.e., FGV<0.50 and U_(RX)%≧50%. In one embodiment, the aluminum alloy body contains (by volumefraction) not greater than 0.45 first type grains (i.e., the aluminumalloy body is at least 55% unrecrystallized (U_(RX) %≧55%), per thedefinitions provided above). In other embodiments, the aluminum alloybody may contain (by volume fraction) not greater than 0.40 first typegrains (U_(RX) %≧60%), or not greater than 0.35 first type grains(U_(RX) %≧65%), or not greater than 0.30 first type grains (U_(RX)%≧70%), or not greater than 0.25 first type grains (U_(RX) %≧75%), ornot greater than 0.20 first type grains (U_(RX) %≧80%), or not greaterthan 0.15 first type grains (U_(RX) %≧85%), or not greater than 0.10first type grains (U_(RX) %≧90%), or less.

ii. Texture

The aluminum alloy body may achieve a unique microstructure. This uniquemicrostructure may be illustrated by the R-values of the aluminum alloybody derived from crystallographic texture data. The microstructure ofan aluminum alloy body relates to its properties (e.g., strength,ductility, toughness, corrosion resistance, among others).

For purposes of the present application, R-values are generatedaccording to the R-value generation procedure, described below.

R-Value Generation Procedure:

-   -   Instrument: An x-ray generator with a computer-controlled pole        figure unit (e.g., Rigaku Ultima III diffractometer (Rigaku USA,        The Woodlands, Tex.) and data collection software and ODF        software for processing pole figure data (e.g., Rigaku software        included with the Rigaku diffractometer) is used. The reflection        pole figures are captured in accordance with “Elements of X-ray        Diffraction” by B. D. Cullity, 2^(nd) edition 1978        (Addison-Wesley Series in Metallurgy and Materials) and the        Rigaku User Manual for the Ultima III Diffractometer and        Multipurpose Attachment (or other suitable manual of other        comparable diffractometer equipment).    -   Sample preparation: The pole figures are to be measured from the        T/4 location to surface. Thus, the sample used for R-value        generation is (preferably) ⅞ inch (LT) by 1¼ inches (L). Sample        size may vary based on measurement equipment. Prior to        measurement of the R-value, the sample may be prepared by:

1. machine the rolling plane from one side to 0.01″ thicker than the T/4plane (if thickness justifies); and

2. chemically etching to the T/4 location.

-   -   X-Ray measurement of pole figures: Reflection of pole figure        (based on Schulz Reflection Method)    -   1. Mount a sample on the sample ring holder with an indication        of the rolling direction of the sample    -   2. Insert the sample holder unit into the pole figure unit    -   3. Orient the direction of the sample to the same horizontal        plane of the pole figure unit)(β=0°)    -   4. Use a normal divergence slit (DS), standard pole figure        receiving slit (RS) with Ni K_(β) filter, and standard scatter        slit (SS) (slit determination will depend on radiation used, the        2θ of the peaks, and the breadth of the peaks). The Rigaku        Ultima III diffractometer uses ⅔ deg DS, 5 mm RS, and 6 mm SS.    -   5. Set the power to recommended operating voltage and current        (default 40 KV 44 mA for Cu radiation with Ni filter on the        Ultima III)    -   6. Measure the background intensity from α=15°, β=0° to α=90°,        β=355° of the Al₍₁₁₁₎, Al₍₂₀₀₎, and Al₍₂₂₀₎ peaks at 5° steps        and counting for 1 second at each step (three pole figures are        usually sufficient for an accurate ODF)    -   7. Measure the peak intensity from α=15°, β=0° to α=90°, β=355°        of Al₍₁₁₁₎, Al₍₂₀₀₎, Al₍₂₂₀₎, and Al₍₃₁₁₎ peaks at 5° steps and        counting for 1 second at each step    -   8. During measurements, the sample should be oscillated 2 cm per        second to achieve a larger sampling area for improved sampling        statistics    -   9. Subtract the background intensity from the peak intensity        (this is usually done by the user-specific software)    -   10. Correct for absorption (usually done by the user-specific        software)        The output data are usually converted to a format for input into        ODF software. The ODF software normalizes the data, calculates        the ODF, and recalculates normalized pole figures. From this        information, R-values are calculated using the        Taylor-Bishop-Hill model (see, Kuroda, M. et al., Texture        optimization of rolled aluminum alloy sheets using a genetic        algorithm, Materials Science and Engineering A 385 (2004)        235-244 and Man, Chi-Sing, On the r-value of textured sheet        metals, International Journal of Plasticity 18 (2002)        1683-1706).

Aluminum alloy bodies produced in accordance with the presentlydescribed methods may achieve high normalized R-values as compared toconventionally produced materials. “Normalized R-value” and the likemeans the R-value as normalized by the R-value of the RV-control sampleat an angle of 0° relative to the rolling direction. For example, if theRV-control sample achieves an R-value of 0.300 at an angle of 0°relative to the rolling direction, this and all other R-values would benormalized by dividing by 0.300.

“RV-control sample” and the like means a control sample taken from areference-version aluminum alloy body in a T4 temper (defined above).

“Rolling direction” and the like means the L-direction for rolledproducts (see, FIG. 13). For non-rolled products, and in the context ofR-values “rolling direction” and the like means the principle directionof extension (e.g., the extrusion direction). For purposes of thepresent application, the various R-values of a material are calculatedfrom an angle of 0° to an angle of 90° relative to the rollingdirection, and in increments of 5°. For purposes of simplicity,“orientation angle” is sometimes used to refer to the phrase “anglerelative to the rolling direction”.

“Maximum normalized R-value” and the like means the maximum normalizedR-value achieved at any angle relative to the rolling direction.

“Max RV angle” and the like means the angle at which the maximumnormalized R-value is achieved.

As a non-limiting example, a chart containing R-values (bothnon-normalized and normalized) of an RV-control sample and an aluminumalloy body processed in accordance with the new processes describedherein is provided in Table 2, below.

TABLE 2 Normalized Normalized R-value R-value Rolling R-value R-value(New Process) (New Process) Angle (Control) (Control) (75% CW) (75% CW)0 0.2955 1.000 0.8221 2.782 5 0.2951 0.999 0.8114 2.746 10 0.2847 0.9640.8172 2.766 15 0.2900 0.981 0.9512 3.219 20 0.2836 0.960 1.2210 4.13225 0.2797 0.947 1.5193 5.142 30 0.2863 0.969 1.8324 6.202 35 0.30291.025 2.2487 7.611 40 0.3171 1.073 2.6125 8.842 45 0.3111 1.053 2.94879.980 50 0.3091 1.046 3.1847 10.779 55 0.2955 1.000 3.0884 10.452 600.2793 0.945 3.0181 10.215 65 0.2662 0.901 2.5006 8.463 70 0.2588 0.8761.7369 5.879 75 0.2736 0.926 1.4054 4.757 80 0.2684 0.908 1.1776 3.98585 0.2716 0.919 0.9738 3.296 90 0.2733 0.925 0.9007 3.049

The normalized R-values for the Control and the 75% Cold Work samplesare plotted as function of orientation angle in FIG. 10. FIG. 10 alsocontains the normalized R-values for aluminum alloy bodies with 25%, 50%and 85% cold work.

As illustrated in FIG. 10, the example aluminum alloy bodies achievemuch higher R-values than the RV-control sample, especially betweenorientation angles of 20° and 70° relative to the rolling direction. Forthe 75% cold worked body, a maximum normalized R-value of 10.779 isachieved at a max RV angle of 50°. The RV-control sample achieves amaximum normalized R-value of 1.073 at a max RV angle of 40°. TheseR-values may be indicative of the texture (and hence microstructure) ofthe new aluminum alloy bodies as compared to conventionally producedaluminum alloy bodies.

In one approach, an aluminum alloy body processed in accordance with thenew methods described herein may achieve a maximum normalized R-value ofat least 2.0. In one embodiment, the new aluminum alloy body may achievea maximum normalized R-value of at least 2.5. In other embodiments, thenew aluminum alloy body may achieve a maximum normalized R-value of atleast 3.0, or at least 3.5, or at least 4.0, or at least 4.5, or atleast 5.0, at least 5.5, or at least 6.0, or at least 6.5, or at least7.0, or at least 7.5, or at least 8.0, or at least 8.5, or at least 9.0,or at least 9.5, or at least 10.0, or at least 10.25, or higher. Themaximum normalized R-value may be achieved at an orientation angle offrom 20° to 70°. In some embodiments, the maximum normalized R-value maybe achieved at an orientation angle of from 30° to 70°. In otherembodiments, the maximum normalized R-value may be achieved at anorientation angle of from 35° to 65°. In yet other embodiments, themaximum normalized R-value may be achieved at an orientation angle offrom 40° to 65°. In yet other embodiments, the maximum normalizedR-value may be achieved at an orientation angle of from 45° to 60°. Inother embodiments, the maximum normalized R-value may be achieved at anorientation angle of from 45° to 55°.

In another approach, an aluminum alloy body processed in accordance withthe new methods described herein may achieve a maximum normalizedR-value that is at least 200% higher than the RV-control sample at themax RV angle of the new aluminum alloy body. In this approach, thenormalized R-value of the new aluminum alloy body is compared to thenormalized R-value of the RV-control sample at the angle where the maxRV angle of the new aluminum alloy body occurs. For example, as shown inFIG. 10 and Table 2, above, the 75% cold worked aluminum alloy bodyrealizes a 1030% increase in normalized R-value at its max RV angle of50° as compared to the normalized R-value of the RV-control sample atthe same angle of 50° (10.779/1.046*100%=1030%). In one embodiment, analuminum alloy body may achieve a maximum normalized R-value that is atleast 250% higher than the RV-control sample at the max RV angle of thenew aluminum alloy body. In other embodiments, the aluminum alloy bodymay achieve a maximum normalized R-value that is at least 300% higher,or at least 350% higher, or at least 400% higher, or at least 450%higher, or at least 500% higher, or at least 550% higher, or at least600% higher, or at least 650% higher, or at least 700% higher, or atleast 750% higher, or at least 800% higher, or at least 850% higher, orat least 900% higher, or at least 950% higher, or at least 1000% higher,or at least 1025% higher, or more, than the RV-control sample at the maxRV angle of the aluminum alloy body.

In another approach, an aluminum alloy body processed in accordance withthe new methods described herein may achieve a maximum normalizedR-value that is at least 200% higher than the maximum normalized R-valueof the RV-control sample. In this approach, the maximum normalizedR-value of the new aluminum alloy body is compared to the maximumnormalized R-value of the RV-control sample, irrespective of the angleat which the maximum normalized R-values occur. For example, as shown inFIG. 10 and Table 2, above, the 75% cold worked aluminum alloy bodyalloy realizes a maximum normalized R-value of 10.779 at an orientationangle of 50°. The maximum normalized R-value of the RV-control sample is1.073 at an orientation angle of 40°. Thus, the 75% cold worked aluminumalloy body realizes a 1004% increase in maximum normalized R-value overthe RV-control sample (10.779/1.073=1004%). In one embodiment, analuminum alloy body may achieve a maximum normalized R-value that is atleast 250% higher than the maximum normalized R-value of the RV-controlsample. In other embodiments, the aluminum alloy body may achieve amaximum normalized R-value that is at least 300% higher, or at least350% higher, or at least 400% higher, or at least 450% higher, or atleast 500% higher, or at least 550% higher, or at least 600% higher, orat least 650% higher, or at least 700% higher, or at least 750% higher,or at least 800% higher, or at least 850% higher, or at least 900%higher, or at least 950% higher, or at least 1000% higher, or more, thanthe maximum normalized R-value of the RV-control sample.

iii. Micrographs

Optical micrographs of some Al—Li alloys bodies produced in accordancewith the new processes described herein are illustrated in FIGS. 11 b-11e. FIG. 11 a is a microstructure of a reference-version of the aluminumalloy body in the T6 temper. FIGS. 11 b-11 e are microstructures of newaluminum alloy bodies having 25%, 50%, 75% and 85% cold work,respectively. These micrographs illustrate some aspects of the uniquemicrostructures that may be attained using the new processes describedherein. As illustrated, the grains of the new aluminum alloy bodiesappear to be non-equiaxed (elongated) grains. For the 75% and 85%cold-worked bodies, the grain structure appears fibrous/rope-like, andwith a plurality of shear bands. These unique microstructures maycontribute to the improved properties of the new aluminum alloy bodies.

F. Optional Post-Thermal Treatments

After the thermal treatment step (300), the Al—Li alloy body may besubjected to various optional final treatment(s) (400). For example,concomitant to or after the thermal treatments step (300), the Al—Lialloy body may be subjected to various additional working or finishingoperations (e.g., (i) forming operations, (ii) flattening orstraightening operations that do not substantially affect mechanicalproperties, such as stretching, and/or (iii) other operations, such asmachining, anodizing, painting, polishing, buffing). The optional finaltreatment(s) step (400) may be absent of any purposeful/meaningfulthermal treatment(s) that would materially affect the microstructure ofthe aluminum alloy body (e.g., absent of any anneal steps). Thus, themicrostructure achieved by the combination of the cold working (200) andthermally treating (300) steps may be retained.

In one approach, one or more of the optional final treatment(s) (400)may be completed concomitant to the thermal treatment step (300). In oneembodiment, the optional final treatment(s) step (400) may includeforming, and this forming step may be completed concomitant to (e.g.,contemporaneous to) the thermal treatment step (300). In one embodiment,the aluminum alloy body may be in a substantially final form due toconcomitant forming and thermal treatment operations (e.g., formingautomotive door outer and/or inner panels, body-in-white components,hoods, deck lids, and similar components during the thermal treatmentstep, among the other products listed in the Product Applicationssection (Section I), below). In one embodiment, an aluminum alloy bodyis in the form of a predetermined shaped product after the formingoperation. In one embodiment, and with reference back to FIG. 2 q-6, athermal treatment step (300) may consist of the warm forming step(320′), and a predetermined shaped product may be produced.

Since optional final treatment(s) (400) may include forming operations(e.g., room temperature or warm forming operations for formingpredetermined shaped products), some work (warm or cold) may be inducedin the body due to such forming operations, but such forming operationsare not included in the definition of “cold working” relative to step(200) when such forming operations either (i) occur after the thermallytreatment step (300) is accomplished (completed), or (ii) occur before,during, or concomitant to the thermal treatment step (300) (i.e., beforethe thermal treatment step is accomplished (completed)), but induce lessthan 0.3322 equivalent plastic strain (i.e., less than 25% CW, per Table1, above). Conversely, any forming operation that occurs at cold workingtemperature(s) (defined above) and induces at least 0.3322 equivalentplastic strain after solutionizing and prior to completion of thethermal treatment step is “cold working”, per above, and is thusincluded in the definition of cold working step (200), and not in thedefinition of the optional final treatment step (400).

As used herein, a “predetermined shaped product” and the like means aproduct that is formed into a shape via a shape forming operation (e.g.,drawing, ironing, warm forming, flow forming, shear forming, spinforming, doming, necking, flanging, threading, beading, bending,seaming, stamping, hydroforming, and curling, among others), and whichshape was determined in advance of the shape forming operation (step).Examples of predetermined shaped products include automotive components(e.g., hoods, fenders, doors, roofs, and trunk lids, among others) andcontainers (e.g., food cans, bottles, among others), consumer electroniccomponents (e.g., as laptops, cell phones, cameras, mobile musicplayers, handheld devices, computers, televisions, among others), andmany other aluminum alloy products described in the Product Applicationssection (Section I), below. For the purposes of this patent application,“predetermined shaped products” do not include mere sheet or plateproducts as produced after cold rolling, since rolling is not a “formingoperation” as defined herein, and rolled products are thus not “formedinto a shape by a shape forming operation”. Instead rolled product arelater shaped (formed) into the final product form by a customer. In oneembodiment, the predetermined shaped product is in its final productform after the forming operation. The forming operation utilized toproduce “predetermined shaped products” may occur before, after orconcomitant to the thermally treating step (300), such as described inthe Thermal Treatment section (Sections C, subsection i).

In one embodiment, a predetermined shaped product is a product producedby flow forming. Flow forming is an incremental metal forming techniquein which a disk or tube of metal is formed over a mandrel by one or morerollers using pressure, where the roller deforms the workpiece, forcingit against the mandrel, usually both axially lengthening the workpiecewhile radially thinning the workpiece. By way of illustration, aluminumalloy bodies that may be produced via flow forming include aerospacecomponents, bases (e.g., table, flag pole, lavatory), basins, bearinghousings, bowls, bullet headlight shapes, clutch housings, cones,containers, covers, lids, caps, military parts, dishes, domes, engineparts, feeders, funnels, hemispheres, high pressure gasbottles/cylinders, hoppers, horns (sound projection), housings, mountingrings, musical instruments (e.g., trumpets, cymbals), nose cones,nozzles, oil seal components, pipe/tube ends, pots, pans, cups, cans,pails, buckets, canisters, pulleys, reflectors, rings, satellite/antennadishes, separator parts, spheres, tank ends/heads/bottoms, venturishapes, waste receptacles, hubs, rollers, struts, torque tubes, driveshafts, engine and motor shafts, munitions and wheels (automotive,truck, motorcycle, etc.), among others.

As noted above, the forming operation may be completed before, during,or after the thermal treatment step (300). In one embodiment, theforming operation is completed concomitant to the thermal treatment step(300), and thus may occur at a temperature of from 150° F. to below therecrystallization temperature of the rolled aluminum alloy product.These forming operations are referred to herein as “warm forming”operations. In one embodiment, a warm forming operation occurs at atemperature of from 200° F. to 550° F. In another embodiment, a warmforming operation occurs at a temperature of from 250° F. to 450° F.Since such forming operations are completed as part of the thermaltreatment step (300), they may be used in combination with any of theembodiments described in the Thermal Treatment section (Section C),above, including any of the embodiments illustrated in FIGS. 2 a, 3-5, 6a, 7-9, 2 q-1 to 2 q-9, among others, described above. Thus, in someembodiments, warm forming may be used to produce predetermined shapedproducts and in a predetermined condition, as described in the ThermalTreatment section (Section C), above, including any of the embodimentsillustrated in FIGS. 2 q-1 to 2 q-9, among others, described above,which warm formed parts may have higher strength as compared to one ormore of (i) their strength in the as-received condition and (ii) areference version of the predetermined shaped product in the T6 temper.The “as-received condition” and the like includes the partially coldworked condition (per step 220), the as-cold worked condition (fullcompletion of step 200, and per the definition of as-cold workedcondition, below), the T3 condition (full completion of step 200, andper the definition of T3 temper, below), or the partially thermallytreated condition (per step 320), and combinations thereof. The improvedproperties may be any of the improved properties described in theProperties section (Section H), below. Warm forming may facilitateproduction of defect-free predetermined shaped products. Defect-freemeans that the components are suitable for use as a commercial product,and thus may have little (insubstantial) or no cracks, wrinkles,Ludering, thinning and orange peel, to name a few. In other embodiments,room temperature forming may be used to produce defect-freepredetermined shaped products.

In other embodiments, the forming operation may occur at temperatures ofless than 150° F., such as at ambient conditions (“room temperatureforming”), and thus are not a part of the thermal treatment step (300).

The above-described forming operations typically apply a strain to analuminum alloy body (e.g., applying a strain to a rolled aluminum alloyproduct, such as an aluminum alloy sheet or aluminum alloy plate) toform the aluminum alloy body into the predetermined shaped product. Theamount of strain may vary during the forming operation, but the maximumamount of strain applied during the forming operation is usually atleast 0.01 EPS (equivalent plastic strain). In one embodiment, themaximum amount of strain applied during the forming operation is atleast 0.05 EPS. In another embodiment, the maximum amount of strainapplied during the forming operation is at least 0.07 EPS. In yetanother embodiment, the maximum amount of strain applied during theforming operation is at least 0.10 EPS. In another embodiment, themaximum amount of strain applied during the forming operation is atleast 0.15 EPS. In yet another embodiment, the maximum amount of strainapplied during the forming operation is at least 0.20 EPS. In anotherembodiment, the maximum amount of strain applied during the formingoperation is at least 0.25 EPS. In yet another embodiment, the maximumamount of strain applied during the forming operation is at least 0.30EPS. In any of these embodiments, the maximum amount of strain appliedduring the forming operation may be less than 0.3322 EPS.

After the forming step, the predetermined shaped product may bedistributed and/or otherwise used by the user of the forming step. Forexample, an automotive manufacturer may form an automotive component,and then assemble a vehicle using the automotive component. An aerospacevehicle manufacturer may form an aerospace component, and then assemblean aerospace vehicle using the aerospace component. A containermanufacturer may form a container, and then provide such container to afood or beverage distributor for filing and distribution forconsumption. Many other variations exist, and many of the aluminum alloyproducts listed in the Product Applications section (Section I), belowcan be formed by manufacturers and then otherwise used in an assemblyand/or distributed.

G. Composition

As noted above, the aluminum alloy body is made from a Al—Li alloy. Forpurposes of the present application, Al—Li alloys are aluminum alloyshaving at least 0.25 wt. % Li, and up to 5.0 wt. % Li. The Al—Li alloymay also include secondary elements, tertiary elements and/or otherelements, as defined below. In some embodiments, the lithium is thepredominate alloying ingredient, other than aluminum. In othersembodiments, at least one of the secondary elements, described below, isthe predominate alloying ingredient, other than aluminum. The lithium,secondary elements and/or tertiary elements may promote a strainhardening response, a precipitation hardening response, and combinationsthereof. In one embodiment, at least some of the alloying elementspromote both a strain hardening response and a precipitation hardeningresponse. In turn, improved properties may be realized.

In one embodiment, the Al—Li alloy includes at least 0.50 wt. % Li. Inanother embodiment, the Al—Li alloy includes at least 0.7 wt. % Li. Inone embodiment, the Al—Li alloy includes not greater than 4.0 wt. % Li.In another embodiment, the Al—Li alloy includes not greater than 3.0 wt.% Li. In another embodiment, the Al—Li alloy includes not greater than2.5 wt. % Li. In another embodiment, the Al—Li alloy includes notgreater than 2.0 wt. % Li.

The Al—Li alloy may include secondary elements. The secondary elementsare selected from the group consisting of copper, magnesium, zinc, andcombinations thereof.

When copper is used, the Al—Li alloy generally includes at least 0.25wt. % Cu. When copper is the predominate alloying element other thanaluminum, the Al—Li alloy generally includes at least 2.0 wt. % Cu, suchas at least 2.5 wt. % Cu. In these embodiments, the Al—Li alloygenerally includes not greater than 6.0 wt. % Cu, such as not greaterthan 4.5 wt. % Cu. When copper is not the predominate alloying elementother than aluminum, the Al—Li alloy generally includes from 0.25 wt. %to 2.0 wt. % Cu, such as from 0.50 to 1.5 wt. % Cu. In otherembodiments, copper may be present as an impurity, and in theseembodiments is present at levels of 0.24 wt. % or less.

When magnesium is used, the Al—Li alloy generally includes at least 0.10wt. % Mg. When magnesium is the predominate alloying element other thanaluminum, the Al—Li alloy generally includes at least 2.0 wt. % Mg, suchas at least 2.5 wt. % Mg. In these embodiments, the Al—Li alloygenerally includes not greater than 12.0 wt. % Mg, such as not greaterthan 8.0 wt. % Mg, or not greater than 6.0 wt. % Mg. When magnesium isnot the predominate alloying element other than aluminum, the Al—Lialloy generally includes from 0.10 wt. % to 2.0 wt. % Mg, such as from0.20 to 1.0 wt. % Mg. In other embodiments, magnesium may be present asan impurity, and in these embodiments is present at levels of 0.09 wt. %or less.

When zinc is used, the Al—Li alloy generally includes at least 0.25 wt.% zinc. When zinc is the predominate alloying element other thanaluminum, the Al—Li alloy generally includes at least 2.0 wt. % zinc,such as at least 4.0 wt. % zinc, or at least 5.0 wt. % zinc. In theseembodiments, the Al—Li alloy generally includes not greater than 22 wt.% Zn, such as not greater than 18 wt. % Zn, or not greater than 15.0 wt.% zinc, or not greater than 12.0 wt. % zinc, or not greater than 10.0wt. % zinc, or not greater than 9.0 wt. % zinc. When zinc is not thepredominate alloying element other than aluminum, the Al—Li alloygenerally includes from 0.25 wt. % to 2.0 wt. % Zn, such as from 0.35wt. % to 1.5 wt. % Zn, or from 0.45 wt. % to 1.0 wt. % Zn. In otherembodiments, zinc may be present as an impurity, and in theseembodiments is present at levels of 0.24 wt. % or less.

The Al—Li alloy may include a variety of tertiary elements for variouspurposes, such as to enhance mechanical, physical or corrosionproperties (i.e. strength, toughness, fatigue resistance, corrosionresistance), to enhance properties at elevated temperatures, tofacilitate casting, to control cast or wrought grain structure, and/orto enhance machinability, among other purposes. When present, thesetertiary elements may include one or more of: (i) up to 2.0 wt. % eachof one or more of Ag, Mn, Si, Fe, Sn, Bi, Pb, Cd, and Ni, (ii) up to 1.0wt. % each of one or more of Sr, Sb, and Cr, and (iii) up to 0.5 wt. %each of one or more of V, Zr, Sc, Ti, Hf, Mo, Co, and rare earthelements. When present, a tertiary element is usually contained in thealloy by an amount of at least 0.01 wt. %.

The Al—Li alloy may include impurities, such as iron and silicon. Whensilicon and/or iron are not included in the alloy as a tertiary element,silicon and/or iron may be included in the Al—Li alloy as an impurity.In these embodiments, the Al—Li alloy generally includes not greaterthan 0.50 wt. % of either silicon and iron. In one embodiment, the Al—Lialloy includes not greater than 0.25 wt. % of either silicon and iron.In another embodiment, the Al—Li alloy includes not greater than 0.15wt. % of either silicon and iron. In yet another embodiment, the Al—Lialloy includes not greater than 0.10 wt. % of either silicon and iron.In another embodiment, the Al—Li alloy includes not greater than 0.05wt. % of at least one of silicon and iron.

The Al—Li alloy generally contains low amounts of “other elements”(e.g., casting aids and impurities, other than Fe and Si). Otherelements means any other element of the periodic table that may beincluded in the Al—Li alloy, except for the aluminum, the lithium, thesecondary elements (when included), the tertiary elements (whenincluded), and the Fe and Si impurities (when included), describedabove. When any element of the secondary and/or tertiary elements iscontained within the alloy only as an impurity, such elements fallwithin the scope of “other elements”, except for iron and silicon. Forexample, if an Al—Li alloy includes copper as an impurity, and not as analloying addition, the copper would fall within the scope of “otherelements”. As another example, if Mn, Ag, and Zr are included in theAl—Li alloy as alloying additions, those tertiary elements would notfall within the scope of “other elements”, but the other tertiaryelements would be included within the scope of other elements since theywould be included in the alloy only as an impurity. However, if siliconor iron is contained in the Al—Li alloy as an impurity, they would notfall within the scope of “other elements” since they have their owndefined impurity limits, as described above.

Generally, the aluminum alloy body contains not more than 0.25 wt. %each of any element of the other elements, with the total combinedamount of these other elements not exceeding 0.50 wt. %. In oneembodiment, each one of these other elements, individually, does notexceed 0.10 wt. % in the Al—Li alloy, and the total combined amount ofthese other elements does not exceed 0.35 wt. %, in the Al—Li alloy. Inanother embodiment, each one of these other elements, individually, doesnot exceed 0.05 wt. % in the Al—Li alloy, and the total combined amountof these other elements does not exceed 0.15 wt. % in the Al—Li alloy.In another embodiment, each one of these other elements, individually,does not exceed 0.03 wt. % in the Al—Li alloy, and the total combinedamount of these other elements does not exceed 0.1 wt. % in the Al—Lialloy.

In one approach, the Al—Li alloy includes:

0.25 to 5.0 wt. % Li;

optionally one or more of the secondary elements of:

-   -   0.10 to 12.0 wt. % Mg,    -   0.25 to 8.0 wt. % Cu, and    -   0.10 to 22.0 wt. % Zn,

optionally with one or more of the tertiary elements of:

-   -   (i) up to 2.0 wt. % each of one or more of Ag, Mn, Si, Fe, Sn,        Bi, Pb, and Ni,    -   (ii) up to 1.0 wt. % each of one or more of Sr, Sb, and Cr and    -   (iii) up to 0.5 wt. % each of one or more of V, Zr, Sc, Ti, Hf,        Mo, Co, and rare earth elements;

if not included in the Al—Li alloy as a tertiary element:

-   -   up to 0.5 wt. % Fe as an impurity;    -   up to 0.5 wt. % Si as an impurity;        the balance being aluminum and other elements, wherein the other        elements are limited to not more than 0.25 wt. % each, and not        more than 0.5 wt. % in total.

The total amount of the primary, secondary, and tertiary alloyingelements should be chosen so that the aluminum alloy body can beappropriately solutionized (e.g., to promote hardening while restrictingthe amount of constituent particles).

In one embodiment, the Al—Li alloy is one of the following wrought Al—Lialloys, as defined by the Aluminum Association: 2020, 2050, 2060, 2090,2091, 2094, 2095, 2195, 2196, 2097, 2197, 2297, 2397, 2098, 2198, 2099,2199, 8024, 8090, 8091, and 8093. In another embodiment, the Al—Li alloyis one of Russian Alloys 01420 and 01421, and related alloys.

In one embodiment, the Al—Li alloy includes an amount of alloyingelements that leaves the Al—Li alloy free of, or substantially free of,soluble constituent particles after solutionizing. In one embodiment,the Al—Li alloy includes an amount of alloying elements that leaves thealuminum alloy with low amounts of (e.g., restricted/minimized)insoluble constituent particles after solutionizing. In otherembodiments, the Al—Li alloy may benefit from controlled amounts ofinsoluble constituent particles.

H. Properties

The new Al—Li alloy bodies produced by the new processes describedherein may achieve (realize) an improved combination of properties.

i. Strength

As mentioned above, the cold working (200) and the thermally treating(300) steps may be accomplished to achieve an increase in strength ascompared to the aluminum alloy body in the as cold-worked condition, theT6 and/or the T87 temper. Strength properties are generally measured inaccordance with ASTM E8 and B557, but may be measured in accordance withother applicable standards, as appropriate to the product form (e.g.,use of NASM 1312-8 and/or NASM 1312-13 for fasteners).

In one approach, the aluminum alloy body achieves at least a 5% increasein strength (TYS and/or UTS) relative to the aluminum alloy body in theT6 condition. In one embodiment, the aluminum alloy body achieves atleast a 6% increase in tensile yield strength relative to the aluminumalloy body in the T6 condition. In other embodiments, the aluminum alloybody achieves at least an 8% increase in tensile yield strength, or atleast a 10% increase in tensile yield strength, or at least a 12%increase in tensile yield strength, or at least a 14% increase intensile yield strength, or at least a 16% increase in tensile yieldstrength, or at least an 18% increase in tensile yield strength, or atleast a 20% increase in tensile yield strength, or at least a 22%increase in tensile yield strength, or at least a 24% increase intensile yield strength, or at least a 26% increase in tensile yieldstrength, or at least a 28% increase in tensile yield strength, or atleast a 30% increase in tensile yield strength, or at least a 32%increase in tensile yield strength, or at least a 34% increase intensile yield strength, or at least a 36% increase in tensile yieldstrength, or at least a 38% increase in tensile yield strength, or atleast a 40% increase in tensile yield strength, or at least a 42%increase in tensile yield strength, or at least a 44% increase intensile yield strength, or at least a 46% increase in tensile yieldstrength, or at least a 48% increase in tensile yield strength, or atleast a 50% increase in tensile yield strength, or at least a 52%increase in tensile yield strength, or at least a 54% increase intensile yield strength, or at least a 56% increase in tensile yieldstrength, or at least a 58% increase in tensile yield strength, or more,relative to the aluminum alloy body in the T6 condition. These increasesmay be realized in the L and/or LT directions. When the aluminum alloybody is a fastener, its tensile yield strength may be tested inaccordance with NASM 1312-8, and may realize any of the improvementsdescribed above or below relative to tensile yield strength.

In a related embodiment, the aluminum alloy body may achieve at least a6% increase in ultimate tensile strength relative to a reference-versionof the aluminum alloy body in the T6 condition. In other embodiments,the aluminum alloy body may achieve at least an 8% increase in ultimatetensile strength, or at least a 10% increase in ultimate tensilestrength, or at least a 12% increase in ultimate tensile strength, or atleast a 14% increase in ultimate tensile strength, or at least a 16%increase in ultimate tensile strength, or at least an 18% increase inultimate tensile strength, or at least a 20% increase in ultimatetensile strength, or at least a 22% increase in ultimate tensilestrength, or at least a 24% increase in ultimate tensile strength, or atleast a 26% increase in ultimate tensile strength, or at least a 28%increase in ultimate tensile strength, or at least a 30% increase inultimate tensile strength, or at least a 32% increase in ultimatetensile strength, or at least a 34% increase in ultimate tensilestrength, or at least a 36% increase in ultimate tensile strength, ormore, relative to a reference-version of the aluminum alloy body in theT6 condition. These increases may be realized in the L and/or LTdirections.

In a related embodiment, an aluminum alloy fastener may achieve at leasta 2% increase in shear strength relative to a reference version of thealuminum alloy fastener, wherein the reference version of the aluminumalloy fastener is in one of a T6 temper and a T87 temper, wherein theshear strength is tested in accordance with NASM 1312-13. In otherembodiments, the aluminum alloy fastener may achieve at least a 4%increase in shear strength, or at least a 6% increase in shear strength,or at least an 8% increase in shear strength, or at a 10% increase inshear strength, or at least a 12% increase in shear strength, or atleast a 14% increase in shear strength, or a 16% increase in shearstrength, or at least an 18% increase in shear strength, or at least a20% increase in shear strength, or at least a 22% increase in shearstrength, or at least a 24% increase in shear strength, or at least a26% increase in shear strength, at least a 28% increase in shearstrength, or at least a 30% increase in shear strength, or at least a32% increase in shear strength, or at least a 34% increase in shearstrength, at least a 36% increase in shear strength, or more, relativeto the reference version of the aluminum alloy fastener, wherein thereference version of the aluminum alloy fastener is in one of a T6temper and a T87 temper.

In one approach, the aluminum alloy body achieves at least equivalenttensile yield strength as compared to a reference-version of thealuminum alloy body in the as-cold worked condition. In one embodiment,the aluminum alloy body achieves at least a 2% increase in tensile yieldstrength as compared to a reference-version of the aluminum alloy bodyin the as-cold worked condition. In other embodiments, the aluminumalloy body achieves at least a 4% increase in tensile yield strength, orat least a 6% increase in tensile yield strength, or at least an 8%increase in tensile yield strength, or at least a 10% increase intensile yield strength, or at least a 12% increase in tensile yieldstrength, or at least a 14% increase in tensile yield strength, or atleast a 16% increase in tensile yield strength, or at least an 18%increase in tensile yield strength, or at least a 20% increase intensile yield strength, or at least a 22% increase in tensile yieldstrength, or at least a 24% increase in tensile yield strength, or atleast a 26% increase in tensile yield strength, or at least a 28%increase in tensile yield strength, or at least a 30% increase intensile yield strength, or at least a 32% increase in tensile yieldstrength, or at least a 34% increase in tensile yield strength, or atleast a 36% increase in tensile yield strength, or at least a 38%increase in tensile yield strength, or at least a 40% increase intensile yield strength, or at least a 42% increase in tensile yieldstrength, or more, as compared to a reference-version of the aluminumalloy body in the as-cold worked condition. Similar results may beobtained relative to ultimate tensile strength. These increases may berealized in the L or LT directions.

In one approach, an aluminum alloy body achieves at least a 5% increasein tensile yield strength relative to the aluminum alloy body in the T87condition. In one embodiment, the aluminum alloy body achieves at leasta 6% increase in tensile yield strength relative to the aluminum alloybody in the T87 condition. In other embodiments, the aluminum alloy bodymay achieve at least an 8% increase in tensile yield strength, or atleast a 10% increase in tensile yield strength, or at least a 12%increase in tensile yield strength, or at least a 14% increase intensile yield strength, or at least a 16% increase in tensile yieldstrength, or at least an 18% increase in tensile yield strength, or atleast a 20% increase in tensile yield strength, or at least a 22%increase in tensile yield strength, or at least a 24% increase intensile yield strength, or at least a 26% increase in tensile yieldstrength, or more, relative to the aluminum alloy body in the T87condition. These increases may be realized in the L and/or LTdirections. Similar results may be obtained relative to ultimate tensilestrength.

In one embodiment, a new Al—Li alloy body realizes a typical tensileyield strength in the LT direction of at least 65 ksi. In otherembodiments, a new Al—Li alloy body realizes a typical tensile yieldstrength in the LT direction of at least 66 ksi, or at least 67 ksi, orat least 68 ksi, or at least 69 ksi, or at least 70 ksi, or at least 71ksi, or at least 72 ksi, or at least 73 ksi, or at least 74 ksi, or atleast 75 ksi, or at least 76 ksi, or at least 77 ksi, or at least 78ksi, or at least 79 ksi, or at least 80 ksi, or at least 81 ksi, or atleast 82 ksi, or at least 83 ksi, or at least 84 ksi, or at least 85ksi, or at least 86 ksi, or at least 87 ksi, or at least 88 ksi, or atleast 89 ksi, or at least 90 ksi, or at least 91 ksi, or at least 92ksi, or at least 93 ksi, or at least 94 ksi, or more. Similar resultsmay be achieved in the longitudinal (L) direction.

In a related embodiment, a new Al—Li alloy body realizes a typicalultimate tensile strength in the LT direction of at least 68 ksi. Inother embodiments, a new Al—Li alloy body realizes a typical ultimatetensile strength in the LT direction of at least 69 ksi, or at least 70ksi, or at least 71 ksi, or at least 72 ksi, or at least 73 ksi, or atleast 74 ksi, or at least 75 ksi, or at least 76 ksi, or at least 77ksi, or at least 78 ksi, or at least 79 ksi, or at least 80 ksi, or atleast 81 ksi, or at least 82 ksi, or at least 83 ksi, or at least 84ksi, or at least 85 ksi, or at least 86 ksi, or at least 87 ksi, or atleast 88 ksi, or at least 89 ksi, or at least 90 ksi, or at least 91ksi, or at least 92 ksi, or at least 93 ksi, or at least 94 ksi, or atleast 95 ksi, or at least 96 ksi, or at least 97 ksi, or at least 98ksi, or at least 99 ksi, or at least 100 ksi, or more. Similar resultsmay be achieved in the longitudinal (L) direction.

The new Al—Li alloy bodies may achieve a high strength and in a shorttime period relative to a reference-version of the Al—Li alloy body inthe T6 and/or T87 temper. In one embodiment, a new Al—Li alloy bodyrealizes its peak strength at least 10% faster than a reference-versionof the aluminum alloy body in the T6 and/or T87 temper. As an example of10% faster processing, if the T6-version of the Al—Li alloy bodyrealizes its peak strength in 35 hours of processing, the new Al—Lialloy body would realize its peak strength in 31.5 hours or less. Inother embodiments, the new Al—Li alloy body realizes it peak strength atleast 20% faster, or at least 25% faster, or at least 30% faster, or atleast 35% faster, or at least 40% faster, or at least 45% faster, or atleast 50% faster, or at least 55% faster, or at least 60% faster, or atleast 65% faster, or at least 70% faster, or at least 75% faster, or atleast 80% faster, or at least 85% faster, or at least 90% faster, ormore, as compared to a reference-version of the aluminum Al—Li alloybody in the T6 and/or T87 temper.

In one embodiment, a new Al—Li alloy body realizes its peak strength inless than 10 hours of thermal treatment time. In other embodiments, anew Al—Li alloy body realizes its peak strength in less than 9 hours, orless than 8 hours, or less than 7 hours, or less than 6 hours, or lessthan 5 hours, or less than 4 hours, or less than 3 hours, or less than 2hours, or less than 1 hour, or less than 50 minutes, or less than 40minutes, or less than 30 minutes, or less than 20 minutes, or less than15 minutes, or less than 10 minutes of thermal treatment time, or less.Due to the short thermal treatment times, it is possible that paintbaking cycles or coating cures could be used to thermally treat the newAl—Li alloy bodies.

ii. Ductility

The aluminum alloy body may realize good ductility and in combinationwith the above-described strengths. In one approach, the aluminum alloybody achieves an elongation (L and/or LT) of more than 4%. In oneembodiment, the aluminum alloy body achieves an elongation (L and/or LT)of at least 5%. In other embodiments, the aluminum alloy body mayachieve an elongation (L and/or LT) of at least 6%, or at least 7%, orat least 8%, or at least 9%, or at least 10%, or at least 11%, or atleast 12%, or at least 13%, or at least 14%, or at least 15%, or atleast 16%, or at least 17%, or more.

iii. Fracture Toughness

The new Al—Li alloy bodies may realize good fracture toughnessproperties. Toughness properties are generally measured in accordancewith ASTM E399 and ASTM B645 for plane-strain fracture toughness (e.g.,K_(IC) and K_(Q)) and in accordance with ASTM E561 and B646 forplane-stress fracture toughness (e.g., K_(app) and K_(R25)).

In one embodiment, the new Al—Li alloy body realizes a toughnessdecrease of not greater than 10% relative to a reference-version of thealuminum alloy body in the T6 and/or T87 temper. In other embodiments,the new Al—Li alloy body realizes a toughness decrease of not greaterthan 9%, or not greater than 8%, or not greater than 7%, or not greaterthan 6%, or not greater than 5%, or not greater than 4%, or not greaterthan 3%, or not greater than 2%, or not greater than 1% relative to areference-version of the Al—Li alloy body in the T6 and/or T87 temper.In one embodiment, the new Al—Li alloy body realizes a toughness atleast equivalent to that of a reference-version of the Al—Li alloy bodyin the T6 temper.

In other embodiments, an aluminum alloy body achieves an improvement infracture toughness. In these embodiments, the new aluminum alloy bodyachieves at least a 1% increase in fracture toughness relative to thealuminum alloy body in the T6 and/or T87 temper. In one embodiment, thenew aluminum alloy body achieves at least a 3% increase in fracturetoughness relative to the aluminum alloy body in the T6 and/or T87temper. In other embodiments, the new aluminum alloy body achieves atleast a 5% increase in fracture toughness, or at least a 7% increase infracture toughness, or at least a 9% increase in fracture toughness, orat least an 11% increase in fracture toughness, or at least a 13%increase in fracture toughness, or at least a 15% increase in fracturetoughness, or at least a 17% increase in fracture toughness, or at leasta 19% increase in fracture toughness, or at least a 21% increase infracture toughness, or at least a 23% increase in fracture toughness, orat least a 25% increase in fracture toughness, or more, relative to thealuminum alloy body in the T6 and/or T87 temper. These increases may berealized in the L-T and/or T-L directions, and may be relative to planestrain fracture toughness (e.g., K_(IC) or K_(Q)) and/or relative toplane stress fracture toughness (e.g., K_(app) or K_(R25)).

iv. Electrical Conductivity

The corrosion performance of the new Al—Li alloy bodies may correlate toelectrical conductivity (e.g., when zinc is utilized in the alloy). Inone embodiment, a new Al—Li alloy body may realize an electricalconductivity of at least 34% IACS. In other embodiments, a new Al—Lialloy body may realize an electrical conductivity of at least 34.5%IACS, or at least 35% IACS, or at least 35.5% IACS, or at least 36%IACS, or at least 36.5% IACS, or at least 37% IACS, or at least 37.5%IACS, or at least 38% IACS, or at least 38.5% IACS, or at least 39%IACS, or at least 39.5% IACS, or at least 40% IACS, or at least 40.5%IACS, or at least 41% IACS, or at least 41.5% IACS, or at least 42%IACS, or at least 42.5% IACS, or at least 43% IACS, or at least 43.5%IACS, or at least 44% IACS, or at least 44.5% IACS, or more. Theseelectrical conductivity values may be achieved in combination withimproved strength and/or other properties.

v. Stress Corrosion Cracking

The new Al—Li alloy bodies may realize good stress corrosion crackingresistance. Stress corrosion cracking (SCC) resistance is generallymeasured in accordance with ASTM G47. For example, a new Al—Li alloybody may achieve a good strength and/or toughness, and with good SCCcorrosion resistance. In one embodiment, a new Al—Li alloy body realizesa Level 1 corrosion resistance. In another embodiment, a new Al—Li alloybody realizes a Level 2 corrosion resistance. In yet another embodiment,a new Al—Li alloy body realizes a Level 3 corrosion resistance. In yetanother embodiment, a new Al—Li alloy body realizes a Level 4 corrosionresistance.

Corrosion Short-transverse stress (ksi) Resistance Level for 20 days(minimum) without failure 1 ≧15 2 ≧25 3 ≧35 4 ≧45

vi. Exfoliation Resistance

The new Al—Li alloy bodies may be exfoliation resistant. For aluminumalloy bodies with high-Zn, exfoliation resistance may be measured inaccordance with ASTM G34. For aluminum alloy bodies with copper orlithium as the predominate alloying ingredient, exfoliation resistancemay be measured in accordance with ASTM G85 (MASTMAASIS testing). Theappropriate exfoliation resistant test may be determined afterenvironment testing at a seacoast location. In one embodiment, analuminum alloy body realizes an EXCO rating of EB or better. In anotherembodiment, an aluminum alloy body realizes an EXCO rating of EA orbetter. In yet another embodiment, an aluminum alloy body realizes anEXCO rating of P, or better.

vii. Appearance

Aluminum alloy bodies processed in accordance with the new processesdisclosed herein may realize improved appearance. The below appearancestandards may be measured with a Hunterlab Dorigon II (Hunter AssociatesLaboratory INC, Reston, Va.), or comparable instrument.

Aluminum alloy bodies processed in accordance with the new processesdisclosed herein may realize at least 5% higher specular reflectance ascompared to the referenced aluminum alloy body in the T6 temper. In oneembodiment, the new aluminum alloy bodies realize at least 6% higherspecular reflectance as compared to the referenced aluminum alloy bodyin the T6 temper. In other embodiments, the new aluminum alloy bodiesrealize at least 7% higher specular reflectance, or at least 8% higherspecular reflectance, or at least 9% higher specular reflectance, or atleast 10% higher specular reflectance, or at least 11% higher specularreflectance, or at least 12% higher specular reflectance, or at least13% higher specular reflectance, or more, as compared to the referencedaluminum alloy body in the T6 temper.

Aluminum alloy bodies processed in accordance with the new processesdisclosed herein may realize at least 10% higher 2 degree diffuseness ascompared to the referenced aluminum alloy body in the T6 temper. In oneembodiment, the new aluminum alloy bodies realize at least 12% higher 2degree diffuseness as compared to the referenced aluminum alloy body inthe T6 temper. In other embodiments, the new aluminum alloy bodiesrealize at least 14% higher 2 degree diffuseness, or at least 16% higher2 degree diffuseness, or at least 18% higher 2 degree diffuseness, or atleast 20% higher 2 degree diffuseness, or at least 22% higher 2 degreediffuseness, or more, as compared to the referenced aluminum alloy bodyin the T6 temper.

Aluminum alloy bodies processed in accordance with the new processesdisclosed herein may realize at least 15% higher 2 image clarity ascompared to the referenced aluminum alloy body in the T6 temper. In oneembodiment, the new aluminum alloy bodies realize at least 18% higher 2image clarity as compared to the referenced aluminum alloy body in theT6 temper. In other embodiments, the new aluminum alloy bodies realizeat least 21% higher 2 image clarity, or at least 24% higher 2 imageclarity, or at least 27% higher 2 image clarity, or at least 30% higher2 image clarity, or more, as compared to the referenced aluminum alloybody in the T6 temper.

Aluminum alloy bodies processed in accordance with the new processesdisclosed herein may realize improved gloss properties. In oneembodiment, an intended viewing surface of an aluminum alloy bodyprocessed in accordance with the new processes disclosed realizes atleast an equivalent 60° gloss value as compared to the intended viewingsurface of a reference version of the aluminum alloy body in the T6temper. In one embodiment, the new aluminum alloy bodies realize atleast a 2% higher 60° gloss value as compared to the intended viewingsurface of a reference version of the aluminum alloy body in the T6temper. In other embodiments, an intended viewing surface of the newaluminum alloy body realizes at a 4% higher 60° gloss value, or at leasta 6% higher 60° gloss value, or at least an 8% higher 60° gloss value,or more, as compared to the intended viewing surface of a referenceversion of the aluminum alloy body in the T6 temper. A “60° gloss value”and the like means the 60° gloss value obtained from measuring theintended viewing surface of the aluminum alloy body using 60° angle ofgloss and a BYK Gardner haze-gloss Reflectometer (or comparable glossmeter) operated according to manufacturer recommended standards.

vi. Surface Roughness

Aluminum alloy bodies processed in accordance with the new processesdisclosed herein may have low surface roughness (e.g., low or noLudering, low or no orange peel, among others). In one embodiment, analuminum alloy body realizes a surface roughness (Ra) of not greaterthan 100 micro-inch (Ra) as measured in the LT direction. In anotherembodiment, the aluminum alloy body realizes a surface roughness (Ra) ofnot greater than 90 micro-inch (Ra) as measured in the LT direction. Inyet another embodiment, the aluminum alloy body realizes a surfaceroughness (Ra) of not greater than 80 micro-inch (Ra) as measured in theLT direction. In another embodiment, the aluminum alloy body realizes asurface roughness (Ra) of not greater than 70 micro-inch (Ra) asmeasured in the LT direction. In yet another embodiment, the aluminumalloy body realizes a surface roughness (Ra) of not greater than 60micro-inch (Ra) as measured in the LT direction. In another embodiment,the aluminum alloy body realizes a surface roughness (Ra) of not greaterthan 50 micro-inch (Ra) as measured in the LT direction, or less. Forpurpose of this subsection (H)(vi), surface roughness is to be measuredon a specimen that has been pulled to fracture via a tensile testconducted in accordance with ASTM E8 and B557.

I. Product Applications

The new processes described herein may have applicability in a varietyof product applications. In one embodiment, a product made by the newprocesses described herein is used in an aerospace application, such aswing skins (upper and lower) or stringers/stiffeners, fuselage skin orstringers, ribs, frames, spars, seat tracks, bulkheads, circumferentialframes, empennage (such as horizontal and vertical stabilizers), floorbeams, seat tracks, doors, and control surface components (e.g.,rudders, ailerons) among others. Many potential benefits could berealized in such components through use of the products including higherstrength, superior corrosion resistance, improved resistance to theinitiation and growth of fatigue cracks, and enhanced toughness to namea few. Improved combinations of such properties can result in weightsavings or reduced inspection intervals or both.

In another embodiment, a product made by the new processes describedherein is used in a munitions/ballistics/military application, such asin ammunition cartridges and armor, among others. Ammunition cartridgesmay include those used in small arms and cannons or for artillery ortank rounds. Other possible ammunition components would include sabotsand fins. Artillery, fuse components are another possible application asare fins and control surfaces for precision guided bombs and missiles.Armor components could include armor plates or structural components formilitary vehicles. In such applications, the products could offer weightsavings or improved reliability or accuracy.

In another embodiment, a product made by the new processes describedherein is used in a fastener application, such as bolts, rivets, screws,studs, inserts, nuts, and lock-bolts, which may be used in theindustrial engineering and/or aerospace industries, among others. Inthese applications, the products could be used in place of other heaviermaterials, like titanium alloys or steels, for weight reduction. Inother cases, the products could provide superior durability.

In another embodiment, a product made by the new processes describedherein is used in an automotive application, such as closure panels(e.g., hoods, fenders, doors, roofs, and trunk lids, among others),wheels, and critical strength applications, such as in body-in-white(e.g., pillars, reinforcements) applications, among others. In some ofthese applications the products may allow down-gauging of the componentsand weight savings.

In another embodiment, a product made by the new processes describedherein is used in a marine application, such as for ships and boats(e.g., hulls, decks, masts, and superstructures, among others). In someof these applications the products could be used to enable down-gaugingand weight reductions. In some other cases, the products could be usedto replace products with inferior corrosion resistance resulting inenhanced reliability and lifetimes.

In another embodiment, a product made by the new processes describedherein is used in a rail application, such as for hopper tank and boxcars, among others. In the case of hopper or tank cars, the productscould be used for the hoppers and tanks themselves or for the supportingstructures. In these cases, the products could provide weight reductions(through down-gauging) or enhanced compatibility with the products beingtransported.

In another embodiment, a product made by the new processes describedherein is used in a ground transportation application, such as for trucktractors, box trailers, flatbed trailers, buses, package vans,recreational vehicles (RVs), all-terrain vehicles (ATVs), and the like.For truck tractors, buses, package vans and RV's, the products could beused for closure panels or frames, bumpers or fuel tanks allowingdown-gauging and reduced weight. Correspondingly, the bodies could alsobe used in wheels to provided enhanced durability or weight savings orimproved appearance.

In another embodiment, a product made by the new processes describedherein is used in an oil and gas application, such as for risers,auxiliary lines, drill pipe, choke-and-kill lines, production piping,and fall pipe, among others. In these applications the product couldallow reduced wall thicknesses and lower weight. Other uses couldinclude replacing alternate materials to improve corrosion performanceor replacing alternate materials to improve compatibility with drillingor production fluids. The products could also be used for auxiliaryequipment employed in exploration like habitation modules and helipads,among others.

In another embodiment, a product made by the new processes describedherein is used in a packaging application, such as for lids and tabs,food cans, bottles, trays, and caps, among others. In theseapplications, benefits could include the opportunity for down-gaugingand reduced package weight or cost. In other cases, the product wouldhave enhanced compatibility with the package contents or improvedcorrosion resistance.

In another embodiment, a product made by the new processes describedherein is used in a reflector, such as for lighting, mirrors, andconcentrated solar power, among others. In these applications theproducts could provide better reflective qualities in the bare, coatedor anodized condition at a given strength level.

In another embodiment, a product made by the new processes describedherein is used in an architecture application, such as for buildingpanels/facades, entrances, framing systems, and curtain wall systems,among others. In such applications, the product could provide superiorappearance or durability or reduced weight associated with down-gauging.

In another embodiment, a product made by the new processes describedherein is used in an electrical application, such as for connectors,terminals, cables, bus bars, and wires, among others. In some cases theproduct could offer reduced tendency for sag for a given currentcarrying capability. Connectors made from the product could haveenhanced capability to maintain high integrity connections over time. Inother wires or cables, the product could provide improved fatigueperformance at a given level of current carrying capability.

In another embodiment, a product made by the new processes describedherein is used in a fiber metal laminate application, such as forproducing high-strength sheet products used in the laminate, amongothers which could result in down-gauging and weight reduction.

In another embodiment, a product made by the new processes describedherein is used in an industrial engineering application, such as fortread-plate, tool boxes, bolting decks, bridge decks, and ramps, amongothers where enhanced properties could allow down-gauging and reducedweight or material usage.

As is specifically relates to tread sheet or tread plate, the newmethods disclosed herein may result in improved tread sheet or treadplate products (“rolled tread products”). A rolled tread product is aproduct having predetermined pattern of raised buttons on an outersurface of a sheet or plate product. A tread sheet has a thickness of0.040 inch to 0.249 inch, and a tread plate has a thickness of 0.250inch to 0.750 inch. The predetermined pattern may be introduced into therolled tread product during cold rolling of an aluminum alloy body usinga roll having a plurality of indentations therein that correspond to thepredetermined pattern, wherein the cold rolling achieves at least 25%cold work. Each of the buttons of the predetermined pattern generallyhas predetermined height, such as a height in the range of 0.197 to0.984 inch. After the cold rolling step (200), the rolled tread productis thermally treated (300), and the combination of the cold rolling step(200) and thermally treating step (300) are accomplished such that therolled tread product realizes improved long-transverse tensile yieldstrength as compared the tread sheet or tread plate in the as coldworked condition. In one embodiment, the rolled tread product realizesat least 5% higher LT tensile yield strength over a referenced rolledtread product, wherein the referenced tread sheet or tread plate has thesame composition as the rolled tread product, but the referenced rolledtread product is processed to a T6 temper (i.e., cold rolled to finalgauge, then solutionized, and then aged to within 1 ksi of its peaktensile yield strength), such as any of the LT yield strength percentageimprovements described in the Properties section (Section H(i)), above,relative to a reference version in the T6 temper. In one embodiment, theproduced tread product is defect-free as defined by EN 1386:1996.

In another embodiment, a product made by the new processes describedherein is used in a fluid container (tank), such as for rings, domes,and barrels, among others. In some cases the tanks could be used forstatic storage. In others, the tanks could be parts of launch vehiclesor aircraft. Benefits in these applications could include down-gaugingor enhanced compatibility with the products to be contained.

In another embodiment, a product made by the new processes describedherein is used in consumer product applications, such as laptops, cellphones, cameras, mobile music players, handheld devices, computers,televisions, microwaves, cookware, washer/dryer, refrigerators, sportinggoods, or any other consumer electronic products requiring durability ordesirable appearance. In another embodiment, a product made by the newprocesses described herein is used in a medical device, securitysystems, and office supplies, among others.

In another embodiment, the new process is applied to a cold holeexpansion process, such as for treating holes to improve fatigueresistance, among others, which may result in a cold work gradient andtailored properties, as described above. This cold hole expansionprocess may be applicable to forged wheels and aircraft structures,among others.

In another embodiment, the new process is applied to cold indirectextrusion processes, such as for producing cans, bottles, aerosol cans,and gas cylinders, among others. In these cases the product couldprovide higher strength which could provide reduced material usage. Inother cases, improved compatibility with the contents could result ingreater shelf life.

In another embodiment, a product made by the new processes describedherein is used in a heat-exchanger application, such as for tubing andfins, among others where higher strength can be translated into reducedmaterial usage. Improved durability and longer life could also berealized.

In another embodiment, the new process is applied to a conformingprocesses, such as for producing heat-exchanger components, e.g., tubingwhere higher strength can be translated into reduced material usage.Improved durability and longer life could also be realized.

Some specific embodiments of some of these product applications aredescribed in the below subsections.

(i) Ammunition Cartridges/Cases

In one approach, the new methods disclosed herein may result in improvedaluminum ammunition cartridges (also called cases or casings). Oneembodiment of a new process for producing aluminum alloy ammunitioncartridges according to the new methods described herein is illustratedin FIG. 2 r. In this method, an aluminum alloy body (2 r-1), such as asheet, plate or extruded rod or bar, may used as a starting material.This material may then be extruded or drawn into member 2 r-2 having abase with an intermediate thickness T1. Member 2 r-2 may then besolutionized, after which the base may be cold worked to a finalthickness of T2 (e.g., via cold heading, cold forging, cold flowforming, and the like), wherein is T2 chosen so as to induce at least25% cold work in the base due to the cold forming operation (2 r-3). Inone embodiment, T2 is chosen so as to induce at least 35% cold work inthe base, such as at least 50% cold work in the base, or more, due tothe cold forming operation. The amount of cold working may be any of thecold working amounts described in the Cold Work section (Section B),above. Due to the amount of work in the base and the subsequent thermaltreatment (300), such cartridges may have a strong base, which may beuseful, for example, to restrict distortion in the firing process and/orfacilitate cartridge extraction. Aluminum alloy cartridges produced viathese methods may have a uniform sidewall (2 r-3 and 2 r-4), such as forshotgun casings and large diameter casings, such as 50-150 mm casings,and the like, among others. In one embodiment, the sidewall is alsoproduced with a high amount of cold work, such as by drawing, ironing,or flow forming, among others. In such embodiments, the sidewall and thebase may receive cold work at the same time (e.g., via flow forming), orthe base and sidewall may receive cold work in separate steps viaseparate cold working operations. Thus, aluminum alloy cartridgesproduced with the new processes disclosed herein may realize improvedproperties in the base, the sidewall, or both, such as any of theimproved properties described in the Properties section (Section H),above. In one embodiment, and as described in the Thermal Treatmentsection (Sections C, subsection i), the aluminum alloy body (2 r-1) maybe solutionized, or solutionized and partially cold worked, prior tobeing formed into the ammunition cartridge.

Aluminum alloy cartridges produced via the method of FIG. 2 r may have aneck portion (2 r-5). This neck portion may be produced after the coldworking step by conventional operations. Local softening at the neck maybe required to facilitate projectile insertion and crimping to secureprojectile in position.

(ii) Armor Components

The new methods disclosed herein may also be useful in producingimproved armor products, bodies and components. In one embodiment, amethod comprises receiving an aluminum alloy armor product, body orcomponent, and attaching the aluminum alloy armor product, body orcomponent as an armor component of an assembly. In this embodiment, theas-received aluminum alloy armor product, body or component may havebeen prepared by the methods described herein, i.e., by solutionizing,then cold working and then thermally treating, such as via any of themethods described in Sections (A)-(C), above. In one embodiment, theassembly is a vehicle. In one embodiment, the vehicle is a militaryvehicle. In another embodiment, the vehicle is a commercial vehicle,such as an automotive vehicle, van, bus, tractor trailer, and the like.In another embodiment, the assembly is a body armor assembly.

An armor component is a component that is designed for use in anassembly, and with the main purpose of stopping one or more projectiles,such as armor piercing projectiles, blasts, and/or fragments. Armorcomponents are usually used in applications where such projectiles couldinjure one or more persons, if not stopped. In one embodiment, analuminum alloy armor component has at least 1% higher V50 ballisticslimit as compared to a reference version of the aluminum alloy armorcomponent in the T6 temper, wherein the V50 ballistics limits is testedin accordance with MIL-STD-662F(1997) (the impact velocity with a 50%probability for perforation for a given alloy and). The V50 ballisticslimit may be for either armor piercing projectiles (AP) and/or fragmentsimulating projectiles (FSP).

In one embodiment, the V50 ballistics limit is armor piercingresistance, and the aluminum alloy armor component has at least 5%higher V50 AP resistance as compared to a reference version of thealuminum alloy armor component in the T6 temper. In other embodiments,the aluminum alloy armor component has at least 6% higher, or at least7% higher, or at least 8% higher, or at least 9% higher, or at least 10%higher V50 AP resistance, or more, as compared to a reference version ofthe aluminum alloy armor component in the T6 temper.

In another embodiment, this V50 ballistics limit is fragment simulatingprojectile resistance, and the aluminum alloy product has at least 2%higher V50 FSP resistance as compared to a reference version of thealuminum alloy armor component in the T6 temper. In other embodiments,the aluminum alloy armor component has at least 3% higher, or at least4% higher, or at least 5% higher V50 FSP resistance, or more, ascompared to a reference version of the aluminum alloy product in the T6temper.

In one embodiment, a new aluminum alloy armor component has a thicknessof from 0.025 inch to 4.0 inch and realizes at least 5% higher V50 armorpiercing resistance as compared to a reference version of the aluminumalloy armor component in the T6 temper. In one embodiment, the aluminumalloy armor component comprises a predominately unrecrystallizedmicrostructure. In one embodiment, the armor component is a plate orforging having a thickness in the range of from 0.250 inch to 4.0 inch.In another embodiment, the armor component is a plate or forging havinga thickness in the range of from 1.0 inch to 2.5 inch. In anotherembodiment, the armor component is a sheet having a thickness of 0.025to 0.249 inch (e.g., for body armor).

(iii) Consumer Electronics

The new methods disclosed herein may also be useful in producingimproved aluminum alloy products for consumer electronic devices. In oneembodiment, a method comprises cold working a solutionized aluminumalloy body and then thermally treating the aluminum alloy body. Themethod may comprise forming the aluminum alloy into a predeterminedshaped product in the form of an outer component for a consumerelectronic product. The forming step may be completed before, after orduring the thermally treating step (300), such as described in theThermal Treatment section (Section C, subsection i), and/or the OptionalPost-Thermal Treatments section (Section F), above.

An “outer component for a consumer electronic product” and the likemeans a product that is generally visible to a consumer of the consumerelectronic product during normal course of use. For example, an outercomponent may be an outer cover (e.g., façade) of a consumer electronicproduct, or a stand or other non-façade portion of the consumerelectronic product. The outer component may have a thickness of from0.015 inch to 0.50 inch. In one embodiment, the outer component is anouter cover for the consumer electronics product and has a thickness offrom 0.015 inch to 0.063 inch.

In one embodiment, a method comprises receiving a rolled or forgedaluminum alloy body, wherein the aluminum alloy body was prepared bysolutionizing and then cold working to final gauge, wherein the coldinduced at least 25% cold work in the aluminum alloy body, wherein thecold working was one of cold rolling and cold forging, and then formingthe rolled aluminum alloy body into an outer component for a consumerelectronic product. In one embodiment, the method comprises thermallytreating the aluminum alloy. In one embodiment, the thermally treatingstep occurs after the receiving step. In one embodiment, the thermallytreating step occurs concomitant to the forming step. In one embodiment,during the forming step, the aluminum alloy body is subjected to atemperature in the range of from at least 150° F. to below therecrystallization temperature of the aluminum alloy body, as per theThermal Treatment section (Section C), above.

In another embodiment, the thermally treating step occurs before thereceiving step, i.e., the aluminum alloy body was at least partiallythermally treated upon receipt. In one embodiment, the forming step iscompleted at less than 150° F. In one embodiment, the forming step iscompleted at ambient conditions.

In any of the above embodiments, the forming step may include applyingstrain to at least a portion of the aluminum alloy body to achieve theouter component, wherein the maximum amount of the strain of theapplying step is equivalent to at least 0.01 equivalent plastic strain,such as any of the forming equivalent plastic strain values listed inthe Optional Post-Thermal Treatments section (Section F), above. Thecold working, thermally treating and forming steps should beaccomplished such that the outer component comprises a predominatelyunrecrystallized microstructure.

The new methods described herein may be useful in producing a variety ofouter components for consumer electronic products, including any of theconsumer electronic products listed above. In one embodiment, theconsumer electronic product is one of a laptop computer, mobile phone,camera, mobile music player, handheld device, desktop computer,television, microwave, washer, dryer, a refrigerator, and combinationsthereof. In another embodiment, the consumer electronic product is oneof a laptop computer, a mobile phone, a mobile music player, andcombinations thereof, and the outer component is an outer cover having athickness of from 0.015 to 0.063 inch.

The new methods described herein may produce outer components havingimproved properties. In one embodiment, the outer component realizes atleast 5% higher normalized dent resistance as compared to a referenceversion of the aluminum alloy outer component in the T6 temper.“Normalized dent resistance” means the dent resistance of an aluminumalloy body as normalized by dividing the inverse of the dent amount (DA)by the thickness of the aluminum alloy body (i.e., (1/DA)/thickness. Forexample, if a dent amount was 0.0250 inch and the product had athickness of 0.0325 inch, its normalized dent resistance would be 94.67per inch². “Dent amount” means the dent size of the dent produced by thedent test procedure, described below. In other embodiments, the outercomponent of a consumer electronic product made from a new aluminumalloy processed according to the new methods described herein realizesat least 10% higher, or at least 15% higher, or at least 20% higher, orat least 25% higher, or at least 30% higher, or more, normalized dentresistance than a reference version of the outer component in the T6temper.

In one embodiment, an outer component of a consumer electronic productmade from a new aluminum alloy processed according to the new methodsdescribed herein realizes at least 5% higher normalized dent resistancethan the same outer component made from alloy 6061 processed to the T6temper. In other embodiments, the outer component of a consumerelectronic product made from a new aluminum alloy processed according tothe new methods described herein realizes at least 10% higher, or atleast 15% higher, or more, normalized dent resistance than the sameouter component made from alloy 6061 processed to the T6 temper.

In one embodiment, an outer component of a consumer electronic productmade from a new aluminum alloy processed according to the new methodsdescribed herein realizes at least 10% higher normalized dent resistancethan the same outer component made from alloy 5052 processed to the H32temper. In other embodiments, the outer component of a consumerelectronic product made from a new aluminum alloy processed according tothe new methods described herein realizes at least 30% higher, or atleast 50% higher, or more, normalized dent resistance than the sameouter component made from alloy 5052 processed to the H32 temper.

The outer component may have an intended viewing surface, and thisintended viewing surface may be free of visually apparent surfacedefects. “Intended viewing surface” and the like means surfaces that areintended to be viewed by a consumer during normal use of the product.Internal surfaces (e.g., the inside of an outer cover) are generally notintended to be viewed during normal use of the product. For example,internal surfaces of a mobile electronic device cover are not normallyviewed during normal use of the product (e.g., when using to send textmessages and/or when using to converse telephonically), but suchinternal surfaces may be occasionally viewed during non-normal usage,such as when changing the battery, and, thus, such internal surfaces arenot intended viewing surfaces. “Free of visually apparent surfacedefects” and the like means that the intended viewing surface of thecover is substantially free of surface defects as viewed by humaneyesight, with 20/20 vision, when the cover is located at least 18inches away from the eyes of the human viewing the cover. Examples ofvisually apparent surface defects include those cosmetic defects thatcan be viewed due to the forming process and/or the alloymicrostructure, among others. The presence of visually apparent surfacedefects is generally determined after anodizing (e.g., immediately afteranodizing, or after application of a coating or other dye/colorant, forinstance). In one embodiment, the outer component realizes maintained orimproved appearance properties, such as any of the appearance propertieslisted in the Properties section (Section H), above. In one embodiment,the intended viewing surface of the outer component realizes at least anequivalent 60° gloss value as compared to an intended viewing surface ofthe reference version reference version of the aluminum alloy outercomponent in the T6 temper. A “60° gloss value” and the like means the60° gloss value obtained from measuring the intended viewing surface ofthe aluminum alloy body using 60° angle of gloss and a BYK Gardnerhaze-gloss Reflectometer (or comparable gloss meter) operated accordingto manufacturer recommended standards.

(iv) Containers

The new methods disclosed herein may also be useful in producing newaluminum alloy containers having improved properties. One method ofproducing a container is illustrated in FIG. 2 s-1, and includes coldworking a solutionized aluminum alloy body into a container (200-C) andthen thermally treating the container (300-C), optionally with finaltreatments (400-C). Examples of cold working steps (200-C), thermaltreatment steps (300-C) and optional final treatment(s) (400-C) that maybe employed to achieve the new aluminum alloy containers are describedin further detail below.

The following definitions apply to this subsection (I)(iv):

-   -   The terms “top”, “bottom”, “below”, “above”, “under”, “over”,        etc. are relative to the position of a finished aluminum alloy        container resting on a flat surface, regardless of the        orientation of the aluminum alloy container during cold working        or forming processes. In some embodiments, the top of the        container has an opening.    -   A “container” is any type of container that may be made from an        aluminum alloy, including but not limited to, beverage cans,        bottles, food cans, aerosol cans, one-piece cans, two-piece cans        and three-piece cans.    -   A “finished aluminum alloy container” is an aluminum alloy        container that will not undergo additional cold working or        forming steps before it is used by an end consumer.    -   “Drawing” means pulling aluminum alloy in the form of a cup and        may include initial drawing, redrawing and deep drawing.    -   “Ironing” means stretching and thinning the walls of a cup via a        punch pushing the sidewall of the cup against ironing rings.    -   “Doming” means producing the base of the container. the base of        the container may be shaped like a dome, may be flat, or may        have an alternate geometry.    -   “Necking” means narrowing the diameter of a portion of the        container.    -   “Flanging” means producing a flange on the container.    -   “Threading” means producing threads on the container.    -   “Beading” means producing a circumferential bead on the sidewall        of the container.    -   “Seaming” is a method of attaching a lid to the container, such        as mechanically bonding and the like.    -   “Curling” means producing a top edge of the container to accept        a closure, such as a lid, an end, lug, threaded closure, a        crown, a roll-on pilfer proof closure, etc.    -   “A reference version of the container in the as cold worked        condition” means a version of the aluminum alloy container that        is prepared identically to the claimed container, but whose        mechanical properties are tested after completion of the cold        working step and prior to the thermal treatment step.        Preferably, the mechanical properties of the reference version        of the container in the as-formed condition are measured within        4-14 days of completion of the cold working step. To produce a        reference version of the container in the as-cold worked        condition, one would cold work the aluminum alloy body into a        container according to the practices described herein, after        which a portion of the aluminum alloy container is removed to        determine its properties in the as cold worked condition per the        requirements described above. Another portion of the aluminum        alloy container would be thermally treated in accordance with        the new processes described herein, after which its properties        would be measured, thus facilitating a comparison between the        properties of a reference version of the container in the as        cold worked condition and the properties of a container        processed in accordance with the new processes described herein        (e.g., to compare dome reversal pressure, vacuum strength,        strength, and/or elongation, among others). Since the both the        new container and the reference version of container in the as        cold worked condition are produced from the same aluminum alloy        container, they would have the same composition. Thus, a        reference-version of the container is comprised of the same        alloy, gauge and geometry as the new container.    -   “Dome reversal pressure” means the threshold pressure above        which the base of the can ‘pops out’ and becomes convex instead        of concave. In some embodiments, the aluminum alloy may be        sufficiently strong to enable the base of the container to be        flat instead of concave. In this case, the dome reversal        pressure means the threshold pressure above which the base of        the can ‘pops out’ and becomes convex instead of flat. Dome        reversal pressure may be measured using an Altek Company        beverage can and lid tester Model 9009C5    -   A “sidewall” is a wall of the side of the container.    -   A “a sidewall of a reference-version of the container in the T6        temper” and the like means a sidewall of a container that has        been solutionized and then thermally treated to a maximum        strength condition (within 1 ksi of peak strength). As described        in further detail below, an aluminum alloy container produced in        accordance with the new processes described herein may achieve        superior properties as compared to the aluminum alloy body in a        T6 temper. To produce a sidewall of a reference-version of the        aluminum alloy container in a T6 temper, one would obtain a        sidewall of an aluminum alloy container, after which a portion        of the sidewall would be processed to a T6 temper (i.e.,        solutionized and then thermally treated to a maximum strength        condition, within 1 ksi of peak strength). Another portion of        the sidewall would be processed (or may have already been        processed) in accordance with the new processes described        herein, thus facilitating a comparison between the properties of        the sidewall of the reference-version of the aluminum alloy        container in the T6 temper and the properties of an aluminum        alloy container processed in accordance with the new processes        described herein (e.g., to compare dome reversal pressure,        vacuum strength, strength, and/or elongation, among others).        Since both sidewalls are obtained from the same aluminum alloy        container, they would have the same composition, gauge and        geometry.    -   “Vacuum strength” means the threshold vacuum pressure above        which the sidewall of the container collapses inwardly. Vacuum        strength may be measured by an Altek Company food Panel Strength        (sidewall collapse resistance) tester—Model 9025.

As mentioned above, the new aluminum alloy containers may be prepared bycold working (200-C) and then thermally treating (300-C). In oneembodiment, an aluminum alloy body, such as a sheet or a slug, is coldworked at least 25% (e.g., by one or more of drawing, ironing and impactextruding), and this cold working step induces at least 25% cold workinto at least a portion of the container, such as by any of the coldwork amounts disclosed in the Cold Working section (Section B), above.In one embodiment, the at least 25% cold work is induced in a part of(or the whole of) the sidewall. In one embodiment, the at least 25% coldwork is induced in a part of (or the whole of) the base. In someembodiments, the cold working step (200-C) comprises cold working atleast a potion of the aluminum alloy body into a container. In someembodiments, the cold working step (200-C) comprises cold working atleast a portion of the aluminum alloy body into a container, and thecold working induces at least 35% cold work, or at least 50% cold work,or at least 75% cold work, or more, into at least a portion of thecontainer. In one embodiment, the cold working operation is initiated ata temperature of less than 150° F.

In one embodiment, the aluminum alloy body is in sheet form prior to thecold working. In any of these embodiments, the aluminum alloy sheet canbe of a thickness appropriate for the container. In some embodiments,because the dome reversal pressure, vacuum strength and/or tensile yieldstrength of the base and/or the sidewall may be greater than that ofprior art containers having the same gauge and geometry, the gauge ofthe container may be reduced as compared to a prior art container havingthe same geometry, while the minimum performance requirements of thecontainer may be maintained. This ability to down-gauge may result inreduced container weight and cost. For example, with respect toproducing a beverage container, the sheet may have a thickness of lessthan 0.0108 inch, or less than 0.0100 inch, or less than 0.0098 inch, orless than 0.0095 inch or less than 0.0094 inch or less than 0.0605 inch.With respect to food cans, the sheet may have a thickness of less than0.0084 inch, or less than 0.0080 inch, or less than 0.0076 inch, or lessthan 0.0074 inch. With respect to aerosol cans, the sheet may have athickness of less than 0.008 inch. In some embodiments, the aluminumalloy sheet is pre-coated, i.e., the aluminum alloy sheet is coated witha coating before the cold working step (200-C).

After the cold working step (200-C), the container may be thermallytreated (300-C). The thermally treating step (300-C) may be accomplishedas per the Thermal Treatment section (Section C), above. In someembodiments, the thermally treating step (300-C) comprises heating thealuminum alloy container in the range of from 150° F. to below therecrystallization temperature of the aluminum alloy body. In oneembodiment, the thermally treating step (300-C) is completed at atemperature of from 150° F. to 600°. In one embodiment, the thermallytreating step (300-C) is completed at a temperature of not greater than550° F., such as not greater than 500° F., or not greater than 450° F.,or not greater than 425° F. In some embodiments, the cold working step(200-C) and the thermally treating step (300-C) are performed such thatthe aluminum alloy container retains or realizes a predominatelyunrecrystallized microstructure (defined in the Microstructure section(Section E), above). As may be appreciated, when higher thermaltreatment temperatures are used, shorter exposure periods may berequired to realize the predominantly unrecrystallized microstructureand/or other desired properties. In one embodiment, the as-receivedaluminum alloy body may have a predominantly unrecrystallizedmicrostructure, such as when the as-received aluminum alloy sheet waspost-solutionized cold rolled by at least 25%. The cold working step(200-C) and thermally treating step (300-C) may be accomplished torealize or retain a predominantly unrecrystallized microstructure(although the microstructure of the container and body may be different,they have a predominantly unrecrystallized microstructure, per thedefinition of Section E). In one embodiment, and with reference now toFIG. 2 s-2, the thermally treating step (300-C) may include steps thatalready occur in standard container making processes, such as insertingthe container into an oven (320-C). For example, after a container hasbeen produced via cold working (e.g., by drawing (220-C) and(optionally) ironing (240-C), or impact extruding (not shown)), thethermally treating step (300-C) may include inserting the container intoan oven (or other heating apparatus) (320-C) so as to, for example, drythe container after washing, cure a coating that was applied to theinside of the container and/or to dry paint applied to the outside ofthe container.

As shown in FIG. 2 s-1, the optional final treatment(s) step (400-C) maybe used to produce the container. In some instances, and as illustratedin FIG. 2 s-1, at least some of the optional final treatments (400) mayoccur after the thermal treatment step (300-C). In some or otherinstances, and with reference now to FIG. 2 s-3, some final treatments(400-C′) occur before or during thermal treatment (300-C). For instance,and as described in further detail below, paint and/or coatings may beapplied after the cold working step (200-C), after which such paintand/or coatings may be cured. In one embodiment, and as described in theabove paragraph, the thermally treating step (300-C) may be used to curesuch paint and/or coatings, and thus at least a portion of the finaltreatment step (400-C) may occur concomitant to at least a portion ofthe thermal treatment step (300-C).

In other embodiments, the paint and/or coatings may be cured at lowtemperatures so as to avoid initiation of thermal treatment (300-C), andpotential hardening of the containers. That is, ovens used to heat thecontainer (or other heating apparatus) may be avoided until thecontainer is in its final form. Since strength may increase upon thermaltreatment, avoiding heat may enable the aluminum alloy container toremain relatively soft until after the container has been finally formed(e.g., via necking, flanging, curling, threading and/or beading orotherwise forming into its final shape). For example, and with referencenow to FIGS. 2 s-4 and 2 s-5, at least some finishing and/or formingoperations (400-C′) may be performed in advance of the thermal treatmentstep (300-C). In the illustrated embodiments, paint and/or coatings, ifapplied, may be cured via radiation, such as UV light, and in theabsence of purposeful conductive heating and/or convective heating ofthe container. In this embodiment, the curing would not thermally treat(300-C) the container because such radiation step would not materiallyheat the aluminum alloy body. In one example, as illustrated in FIG. 2s-4, the cold working a solutionized aluminum alloy sheet into acontainer step (200-C) may comprise drawing the container (220-C) andoptionally, ironing the container (240-C). After the cold working step(200-C), the container may be painted (410-C), then cured via radiation(420-C), and then necked and/or beaded (430-C), after which it isthermally treated (300-C). Similarly, and with reference now to FIG. 2s-5, the cold working a solutionized aluminum alloy sheet into acontainer step (200-C) may comprise drawing the container (220-C) andoptionally, ironing the container (240-C). After the cold working step(200-C), an inside of the container may be coated (410-C), then curedvia radiation (420-C), and then necked and/or beaded (430-C). Thus, theoptional final treatment(s) (400-C and/or 400-C′) step may include“forming operations” (defined in Section F, above), which may includenecking, flanging, beading, curling and/or threading, or otherwiseforming the container into its final shape before, during or after thethermally treating step (300-C).

In some embodiments, since the aluminum alloy may become stronger duringthe container production process, it is possible to start the processwith an aluminum alloy body that is softer and more formable. Suchaluminum alloy bodies may, therefore, be easier to form into complexshapes and/or may be produced in fewer steps than the same containermade by prior art processes.

Due to the unique processing techniques, improved properties may berealized, such as one or more of an improvement in column bucklingstrength, dome reversal pressure and vacuum strength, among others. Inone embodiment, the new aluminum alloy containers realize improvedproperties over a reference version of the aluminum alloy container inthe as-cold worked condition. In another embodiment, the new aluminumalloy containers realize improved properties over a reference version ofthe aluminum alloy container in the T6 temper.

In one embodiment, the cold working and the thermally treating steps areaccomplished to achieve at least a 5% increase in dome reversal pressureas compared to a reference version of the container in the as-coldworked condition. In some of these embodiments, the cold working and thethermally treating steps are accomplished such that the container has adome reversal strength of at least 90 lbs/sq. inch.

In one approach, the cold working step induces at least 25% cold work inat least a portion of a sidewall of a container. In one embodiment, thecold working and the thermally treating steps may be accomplished toachieve at least a 5% increase in tensile yield strength relative to theportion of the sidewall having the at least 25% cold work as compared tothe tensile yield strength of the same sidewall portion of areference-version of the container in the T6 temper, such as any of thetensile yield strength improvements described in the Properties section(Section H), above. In another embodiment, the cold working and thethermally treating steps are accomplished to achieve at least a 5%increase in tensile yield strength relative to the portion of thesidewall having the at least 25% cold work as compared to the tensileyield strength of the same sidewall portion of the container in theas-cold worked condition, such as any of the tensile yield strengthimprovements described in the Properties section (Section H), above. Inanother embodiment, the cold working and the thermally treating stepsare accomplished to achieve at least a 5% improvement in vacuum strengthas compared to the container in the as cold-worked condition. In someembodiments, the cold working and the thermally treating steps areaccomplished such that the container has a vacuum strength of at least24 psi, at least 28 psi, or at least 30 psi, or more. In someembodiments, the sidewall of the container is more puncture resistantthan (i) a prior art container of the same gauge and geometry, (ii) acontainer in the as-cold worked condition, and/or (iii) a referenceversion of the container in the T6 temper.

Even though some embodiments result in a container having enhancedstrength, the formability of the container may be maintained, or evenimproved. For example, in some embodiments, the applicable portion of(or the whole of) the aluminum alloy container may realize an elongationof at least 4%, or at least 5%, or at least 6%, or at least 7%, or atleast 8%, or more.

In any of the above described embodiments, the aluminum alloy body maycontain sufficient solute to promote at least one of a strain hardeningresponse and a precipitation hardening response to achieve the improvedproperty or properties. The potentially improved strength realized bycontainers made by the presently disclosed methods may also facilitateproduction of containers having a flat base or a larger dome window.

In all of the above embodiments of a method of producing a container,the sheet may have been cold worked, for example via cold rolling, priorto cold working into a container, as per the Cold Work section (SectionB) and/or the Thermal Treatment section (Section C).

Referring to FIG. 2 s-6, in some embodiments, the container (800-C) hassidewalls (820-C) and a bottom (840-C), also known as a base or a dome.The aluminum alloy container comprising (800-C) the sidewalls (820-C)and bottom (840-C) may be a single, continuous aluminum alloy sheet. Inother embodiments, and with reference now to FIG. 2 s-7, the containeris a closure (900-C). In some embodiments, the closure is a lid.

(v) Fasteners

In one approach, the new methods disclosed herein may result in improvedfastener products. A “fastener” is a product made from a rolled,extruded, or drawn stock that has the primary purpose of connecting twoor more components. Fasteners made according to the new processesdescribed herein may be prepared for post-solutionizing cold work (100),and then cold worked by more than 25% (200) and then thermally treated(300). In one embodiment, a cold working step (200) comprises coldworking an aluminum alloy body into a fastener by one of cold forging,cold swaging and cold rolling. In one embodiment, a first portion of thecold working step produces a fastener feed stock (e.g., cold worked rod(including wire) or bar), and a second portion of the cold working stepproduces the fastener (e.g., via cold forging or cold swaging). Suchpartial cold working, and similar methods, may be completed as describedin the Thermal Treatment section (Section C, subsection i).

A fastener may be one-piece or a multiple-piece system. A one-piecefastener may have a body and a head. A fastening system has at least twocomponents, such as a first piece with a body and a head, and a secondpiece (locking member) designed to attach to the first piece, such as anut or collar. Examples of fasteners having a body and a head includerivets, screws, nails, and bolts (e.g., lock bolts). Part of a fastenermay have one or more threads. Fasteners have at least 2 primary failuremodes, the first being tension where the primary loading direction isparallel to the centerline of the fastener and shear where the primaryloads are perpendicular to the centerline of the fasteners. Thelongitudinal ultimate tensile strength of the body of the fastener isthe primary factor in determining its failure load in tension and theshear strength is the primary factor in determining its failure load inshear. In one approach, a new aluminum alloy fastener realizes a tensileyield strength and/or ultimate tensile strength that is at least 2%higher than a reference version of the aluminum alloy fastener in theas-cold worked condition and/or the T6 condition, such as any of thetensile yield strength and/or ultimate tensile strength values describedin the Properties section (Section H(i)), above. In one embodiment, anew aluminum alloy fastener realizes a shear strength that is at least2% greater than a reference version of the fastener, such as any of theshear strength values described in the Properties section (SectionH(i)), above, wherein the reference version of the fastener is in a T6temper. The improved strength properties may relate to one or more ofthe pin, head or locking mechanism of the fastener. In one embodiment,the improved strength relates to the pin of the fastener. In anotherembodiment, the improved strength relates to the head of the fastener.In yet another embodiment, the improved strength relates to the lockingmechanism of the fastener. In one approach, a new aluminum alloyfastener had a predominately unrecrystallized microstructure, asdescribed in the Microstructure section (Section E(i)), above.

In one embodiment, a method comprises first cold working an aluminumalloy body into a fastener stock. The method may further comprise secondcold working the fastener stock into a fastener. This second coldworking step may produce the head, the pin and/or the locking member. Athird cold working step may optionally be employed, wherein at least onethread (“threaded portion”) is produced in the fastener (e.g., in thepin and/or the locking member). The combination of the first, second andoptional third cold working steps may result in the fastener having atleast 25% cold work. The aluminum alloy fastener may then be thermallytreated, as provided above. In one embodiment, the first cold workingstep induces at least 25% cold work into the fastener stock. In oneembodiment, the second cold working step induces at least 25% cold workinto the fastener. In one embodiment, the third cold working stepinduces at least 25% cold work into the threaded portion. Thus, one ormore portions of the fastener may have more than 25% cold work, such asany of the cold work amounts described in the Cold Work section (SectionB), above, depending on processing.

(vi) Rods

In one approach, the new methods disclosed herein may result in improvedrod products. A rod product is a rod or wire product, as defined theAluminum Association. In one embodiment, a method comprises preparing analuminum alloy rod for post-solutionizing cold work, described above,after the preparing step, cold working the aluminum alloy rod to finalgauge, wherein the cold working induces at least 25% cold work into therod, and, after the cold working step, thermally treating the aluminumalloy rod, wherein the cold working and the thermally treating steps areaccomplished to achieve an increase in longitudinal ultimate tensilestrength as compared to a reference-version of the aluminum alloy rod inthe as cold-worked condition and/or the T6 temper and/or the T87 temper,or any other of the improved properties described in the Propertiessection (Section H), above. Such improved properties may be realized ina shorter period of time, as described in the Properties section(Section H), above. In one embodiment, the cold working step maycomprise of one cold drawing, cold rod rolling and cold swaging. In oneembodiment, after the cold working, the rod is at wire gauge. In oneapproach, a new aluminum alloy rod realizes an ultimate tensile strengththat is higher than a reference version of the aluminum alloy rod,wherein the reference version is in one of the T6 temper and the T87temper, such as any of the ultimate tensile strength values described inthe Properties section (Section H), above. In one approach, a newaluminum alloy rod had a predominately unrecrystallized microstructure,as described in the Microstructure section (Section E(i)), above.

(vii) Wheels

The new methods described herein may also be useful in producingimproved wheel products. Referring now to FIGS. 2 t-1 and 2 t-2, oneembodiment of wheel (110-W) that may be produced via the new methodsdescribed herein is illustrated. The illustrated wheel (110-W) comprisesa disk face (112-W), a rim (114-W), a drop well (116-W), a bead seat(118-W) and a mounting flange (120-W). The rim (112-W) is the outer partof the wheel on which a tire may be mounted. The mounting flange (120-W)is the location of the wheel attached directly to a vehicle (e.g., incontact with). The disk face (112-W) is located between the rim and themounting flange. The wheel shown in FIGS. 2 t-1 and 2 t-2 is an autowheel. However, it should be appreciated that the new methods describedherein may be applicable to commercial wheels, or any other type ofwheel that may be formed by cold working by at least 25%. Also, thoseskilled in the art know that wheels may have more or fewer parts.

In one embodiment, a solutionized aluminum alloy body (e.g., asolutionized aluminum alloy feedstock, such as ingot) may be cold worked(200), as described in the Cold Work section (Section B), above, whereinthe cold working induces at least 25% cold work into at least a portionof the wheel. For example, during production of the wheel (110-W), thiscold working step may induce at least 25% cold work in at least one ofthe disk face (112-W), the rim (114-W), the drop well (116-W), the beadseat (118-W) and the mounting flange (120-W). In one embodiment, thecold working induces at least 25% cold work in the disk face (112-W). Inone embodiment, the cold working induces at least 25% cold work in therim (114-W). In one embodiment, the cold working induces at least 25%cold work in the drop well (116-W). In one embodiment, the cold workinginduces at least 25% cold work in bead seat (118-W). In one embodiment,the cold working induces at least 25% cold work in the mounting flange(120-W). Higher levels of cold work may be induced, such as any of thecold working amounts described in the Cold Work section (Section B),above. In one embodiment, the cold working step induces at least 35%cold work in at least a portion of the wheel, which portion may be apart of (or the whole of) any of the above-described wheel parts. Inanother embodiment, the cold working step induces at least 50% coldwork, or at least 75% cold work, or at least 90% cold work, in at leasta portion of the wheel, which portion may be a part of (or the whole of)any of the above-described wheel parts. In yet another embodiment, thecold working step induces at least 90% cold work in at least a portionof the wheel, which portion may be a part of (or the whole of) any ofthe above-described wheel parts.

The cold working step may utilize one or more of the followingoperations to cold work and produce the wheel: spinning, rolling,burnishing, flow forming, shear forming, pilgering, swaging, radialforging, cogging, forging, extruding, nosing, hydrostatic forming andcombinations thereof. In one embodiment, the cold working comprises flowforming.

In one embodiment, the cold working step (200) forms a wheel using oneor more forming techniques. The geometric complexity of a desiredcold-formed output shape (e.g., a wheel) has two major forming processconsiderations: (1) the overall shape may be subdivided into sub-regionsthat can be processed more conveniently; and (2) the deformationcharacter will be one of redundant work and high deformation pressures.

The intermediate manufacturing geometry may be subdivided into tworegions. The first region is the disk face (also called the wheel face,head or hub region) that extends from the centerline of the geometry tothe outer radial portion. Second is the wheel rim region (also calledthe tube well or skirt region) that is similar to a short thick-walledcylinder. In this embodiment, consider the disk face and rim regions asconnected in a one-piece wheel design. Although connected, these regionscan be regarded as independent regions where independent deformationprocesses could form the final output shapes of both connected regions.In embodiments where these two regions are separate pieces of amulti-piece wheel design, then independent deformation processes couldbe used to form each piece before joining. In some embodiments thepieces of the multi-piece wheel could be comprised of different aluminumalloys, with at least one of the alloys being a heat treatable aluminumalloy.

In some embodiments, the geometric transformation to the desiredcold-formed output shape requires the use of forming processes withinherent redundant deformation. These processes impart effective strainsthat are greater than those computed by considering only initial andfinal section dimensions. This results in correspondingly higher flowstresses. The material's post-solutionized cold flow stress issignificantly higher than its pre-solutionized cold flow stresscounterpart. Thus, imparting the minimum necessary cold work to form theoutput geometry from the intermediate manufacturing geometry is asignificantly greater challenge in terms of equipment loading than anypre-solutionization deformation forming the intermediate manufacturinggeometry.

There are three general deformation categories available to form thedisk face and rim regions. Some of these operations can be combined orcompleted multiple times to generate both the local thickness andcontour of the desired geometry.

-   -   Incremental Forming—These deformation options are those where        the forming load is concentrated in a small local area on the        component to achieve high forming pressures that can deform a        component. Options to dimension and contour the rim region        include: flow forming, shear forming, spinning, rolling,        pilgering, swaging, cold forging and radial forging. Options to        dimension and contour the face region include: flow forming,        spinning, shear forming, radial forging and cogging (radial        and/or circumferential).    -   Bulk Forming—These deformation options place the component in        open or closed die cavities and exert force via a tool motion to        deform and shape the part. Options to dimension and contour the        rim region include: forging, extrusion, swaging and pilgering.        Options to dimension and contour the disk face region include:        forging, nosing, channeled angular extrusion, radial and/or        circumferential cogging.    -   Hydrostatic Forming—These deformation options place the        component in a closed cavity pressurized by a fluid, but some        surface of the component is not exposed to the pressurized fluid        causing deformation. Hydrostatic fluid pressures several times        greater than the flow stress of the cold solutionized material        are needed to cause deformation. The flow stresses are dependent        on the starting solutionized preform geometry.

Flow forming is an incremental metal forming technique in which a diskor tube of metal is formed over a mandrel by one or more rollers usingpressure, where the roller deforms the workpiece, forcing it against themandrel, usually both axially lengthening the workpiece while radiallythinning the workpiece. Flow forming subjects the workpiece to frictionand deformation. These two factors may heat the workpiece, and this acooling fluid may be required in some instance. Flow forming is oftenused to manufacture automobile wheels and other axisymetric shapedproducts and can be used to draw a wheel to net width from a machinedblank. During flow forming, the workpiece is cold worked, changing itsmechanical properties, so its strength becomes similar to that of forgedmetal.

In one embodiment, a wheel is formed incrementally staring with a flatcylinder having a diameter less than that of the rim, but thick enoughto be deformed at least 25% to form the final face thickness. First, theface may be flow formed against the mandrel's face surface to achievethe final disk thickness and contour. This flow forming operation mayalso displace enough metal outward radially beyond the final rim outerdiameter to make the rim. Alternately, the starting flat cylinder can beformed by cross-rolling a plate to the desired face thickness. Theneeded rim material could be available by having an appropriately sizedlarger starting diameter. Second, the skirt may be flow formed into arim and contoured against a mandrel's rim face. When flow forming amulti-piece wheel, the parts, such as the disk face and rim, can beformed separately using similar incremental forming processes.

In one embodiment involving bulk forming, a starting cylinder ofsolutionized material is forged to form the disk face region and extrudea straight rim. The rim may then be flow formed to the final thicknessand contour. Another option is to swage the rim to the final shape.Alternatively, a solutionized thick-walled cylinder may be forged into ablind face cavity, where it turns radially inward by channeled angularindirect extrusion to form the face region.

In one embodiment involving hydrostatic forming, a solutionized preformhas: (1) the top side dished so that there is more material on the outerdiameter with a minimum height to achieve the minimum cold reduction,and (2) the bottom side with an annular projection about the size of thewheel rim. The preform may then be placed into a hydrostatic chamberwith a bottom annular chamber opening corresponding to the preform'sbottom annular projection. The preform's annular projection may betapered to match the chamber's bottom annular opening to quickly form aseal under pressure. Next, the chamber may be pressurized so the fluidpushes the top surface causing metal flow to exit the annular opening.The extra material at the outer radial region supplies metal forming therim while the middle thinner region thins and pushes metal radiallyoutward to convert the top dish shape to a flatter shape while coldworking the wheel face region.

After the cold working, the wheel may be thermally treated (300), as perthe Thermal Treatment section (Section C), above. In one embodiment, thewheel is thermally treated at a temperature of from 150° F. to below itsrecrystallization temperature. In one embodiment, the thermally treatingstep comprises heating the wheel at a temperature of not greater than425° F. In one embodiment, the thermally treating step comprises heatingthe wheel at a temperature of not greater than 400° F. In oneembodiment, the thermally treating step comprises heating the wheel at atemperature of not greater than 375° F. In one embodiment, the thermallytreating step comprises heating the wheel at a temperature of notgreater than 350° F. In one embodiment, the thermally treating stepcomprises heating the wheel at a temperature of at least 200° F. In oneembodiment, the thermally treating step comprises heating the wheel at atemperature of at least 250° F. In one embodiment, the thermallytreating step comprises heating the wheel at a temperature of at least300° F.

The cold working step (200) and the thermally treating step (300) may beaccomplished to achieve a wheel having improved properties, as describedin the Cold working and thermally-treating combination section (SectionD, above). In one embodiment, the cold working and thermally treatingsteps are accomplished to achieve at least a 5% improvement inlongitudinal (L) tensile yield strength in the cold worked portion ofthe wheel as compared to the longitudinal tensile yield strength in thecold worked portion of the wheel in the as-cold worked condition. Inanother embodiment, the cold working and thermally treating steps areaccomplished to achieve at least a 10% improvement in longitudinaltensile yield strength, or at least a 15% improvement in longitudinaltensile yield strength, or at least a 16% improvement in longitudinaltensile yield strength, or at least a 17% improvement in longitudinaltensile yield strength, or at least a 18% improvement in longitudinaltensile yield strength, or at least a 19% improvement in longitudinaltensile yield strength, or at least a 20% improvement in longitudinaltensile yield strength, or at least a 21% improvement in longitudinaltensile yield strength, or at least a 22% improvement in longitudinaltensile yield strength, or at least a 23% improvement in longitudinaltensile yield strength, or at least a 24% improvement in longitudinaltensile yield strength, or at least a 25% improvement in longitudinaltensile yield strength, or more, in the cold worked portion of the wheelas compared to the longitudinal tensile yield strength in the coldworked portion of the wheel in the as-cold worked condition. In someembodiments, after the thermally treating step, the cold worked portionof the wheel has a longitudinal elongation of at least 4%, such as anyof the elongation values described in the Properties section (SectionH), above. In one embodiment, after the thermally treating step, thecold worked portion of the wheel may have a longitudinal elongation ofat least 6%. In other embodiments, after the thermally treating step,the cold worked portion of the wheel realizes an elongation of at least8%, such as at least 10%, or at least 12%, or at least 14%, or at least16%, or more.

Aluminum alloy wheel products made by the new processes disclosed hereinmay realize another or alternative improved property or properties inthe portion of the wheel having the at least 25% cold work. For example,the portion of the wheel having the at least 25% cold work may realizeat least at least a 5% higher longitudinal tensile yield strength ascompared to the longitudinal tensile yield strength of the same portionof a reference version of the wheel processed to the T6 temper, such asany of the T6 improvements described in the Properties section (SectionH), above.

In any of the above-described embodiments, the aluminum alloy body maycontain sufficient solute to promote at least one of a strain hardeningresponse and a precipitation hardening response to achieve the improvedproperty or properties.

The new wheel products may realize a predominately unrecrystallizedmicrostructure in the portion of the wheel receiving the at least 25%cold work, such as any of the microstructures described in theMicrostructure section (Section E), above. In some embodiments, theportion of the wheel receiving the at least 25% cold work is at least75% unrecrystallized.

In one embodiment a wheel, or other predetermined shaped product, can bean assembly containing at least one component manufactured by thetechniques described herein. In the case of a multi-piece wheel, onecomponent could comprise the rim, drop well and bead seats and anothercould comprise the disk face and or mounting flange. In one embodiment,the assembly could contain different aluminum alloys manufactured usingthe techniques described herein, with at least one of the aluminumalloys being a heat treatable aluminum alloy.

(viii) Multi-Layer Products

The new Al—Li alloy products may find use in multi-layer applications.For example it is possible that a multi-layer product may be formedusing a Al—Li alloy body as a first layer and any of the 1 xxx-8xxxalloys being used as a second layer. FIG. 12 illustrates one embodimentof a method for producing multi-layered products. In the illustratedembodiment, a multi-layered product may be produced (107), after whichit is homogenized (122), hot rolled (126), solutionized (140) and thencold rolled (220), as described above relative to FIG. 9. Themulti-layered products may be produced via multi-alloy casting, rollbonding, adhesive bonding, welding, and metallurgical bonding, amongothers. Multi-alloy casting techniques include those described in U.S.Patent Application Publication No. 20030079856 to Kilmer et al., U.S.Patent Application No. 20050011630 to Anderson et al., U.S. PatentApplication No. 20080182122 to Chu et al., and WO2007/098583 to Novelis(the so-called FUSION™ casting process).

For example, a first layer may be an Al—Li alloy product processed inaccordance with the new processes disclosed herein. A second layer maybe any of a 1xxx-8xxx aluminum alloy product, including another Al—Lialloy product (which may be the same alloy or a different alloy than thefirst Al—Li alloy product). The first and second layers may have thesame thickness, or may be of different thicknesses. Thus, themulti-layer product may realize tailored properties with the first layerrealizing a first set of properties, and the second layer realizing asecond set of properties. Processing of the at least two differentlayers to produce a multi-layer product is discussed in further detailbelow.

In one approach, the second layer comprises a non-heat treatable alloy,such as any of the 1xxx, 3xxx, 4xxx, 5xxx and some 8xxx aluminum alloys.In this approach, a multi-layer product comprises a first layer of anAl—Li alloy product processed in accordance with the new processesdisclosed herein, and at least a second layer of a non-heat treatablealloy, i.e., a AlLi-NHT product, where the AlLi is the first layer andthe NHT is the second layer of a non-heat treatable aluminum alloy.

In one embodiment, the second layer comprises a corrosion resistant typealloy, such as any of the 1xxx, 3xxx, 5xxx and some 8xxx aluminumalloys. In these embodiments, the first layer may provide improvedstrength properties, and the second layer may provide corrosionresistant properties. Since a non-heat treatable alloy is used as thesecond layer, this second layer may not naturally age, and thus mayretain its ductility. Thus, in some instances, the second layer may havehigher ductility and/or a different strength than the first layer.Hence, a multi-layer product with a tailored ductility differential (orgradient) and/or a tailored strength differential (or gradient) may beproduced. In one embodiment, the second layer is the outer layer of amulti-layer product, and the second layer's resistance to ductilitychanges may be useful in hemming operations (e.g., for automotive sheetapplications, such as inner and/or outer door panel applications, amongothers). In one embodiment, the second layer is a 5xxx aluminum alloyhaving at least 3 wt. % Mg. In one embodiment, the second layercomprises an aluminum alloy having improved appearance properties ascompared to the first aluminum alloy layer, such as when the secondlayer is a 1xxx, 3xxx or a 5xxx aluminum alloy.

In another approach, the second layer comprises a heat treatable alloy,such as any of a 2xxx aluminum alloy, a 6xxx aluminum alloy, a 7xxxaluminum alloy, the same or another Al—Li alloy, and some 8xxx aluminumalloys, i.e., a AlLi-HT product, where the AlLi is the first layer andwhere the HT is the second layer of the heat treatable aluminum alloy.Since the second layer is a heat treatable aluminum alloy, it may beprocessed according to the new processes disclosed herein and realizeimproved properties over conventionally processed materials. However, itis not required that the second layer be processed according to the newprocesses disclosed herein, i.e., the second layer of heat treatablematerial may be conventionally processed. Processing of the at least twodifferent layers to produce a multi-layer product is discussed infurther detail below.

In one embodiment, the multi-layer product is a AlLi(1)-AlLi(2) product,where AlLi(1) is a first layer of an Al—Li alloy product producedaccording to the processes disclosed herein, and AlLi(2) is a secondfirst layer of an Al—Li aluminum alloy product, which second layer maybe conventionally processed or may be produced according to theprocesses disclosed herein. In this embodiment, the first and secondlayers have at least one compositional difference or at least oneprocessing difference. In one embodiment, AlLi(1) has a differentcomposition than AlLi(2). In one embodiment, AlLi(1) receives adifferent amount of cold work relative to AlLi(2). In one embodiment,AlLi(1) receives a different thermal treatment practice relative toAlLi(2). Such multi-layer products may find applicability in automotiveapplications, among others.

In one embodiment, a multi-layer product is a AlLi-7xxx product, wherethe AlLi is a first layer of a AlLi aluminum alloy product producedaccording to the processes disclosed herein, and the 7xxx is a secondlayer of a 7xxx aluminum alloy product, which may or may not be producedin accordance with the processes disclosed herein. Such multi-layerproducts may find applicability in automotive, aerospace and armorapplications, among others.

In one embodiment, a multi-layer product is a AlLi-2xxx product, wherethe AlLi is a first layer of AlLi aluminum alloy product producedaccording to the processes disclosed herein, and the 2xxx is a secondlayer of a 2xxx aluminum alloy product, which may or may not be producedin accordance with the processes disclosed herein. Such multi-layerproducts may find applicability in automotive, aerospace and armorapplications, among others.

In one embodiment, a multi-layer product is a Al—Li-6xxx product, wherethe Al—Li is a first layer of a Al—Li aluminum alloy product producedaccording to the processes disclosed herein, and the 6xxx is a secondlayer of a 6xxx aluminum alloy product, which may or may not be producedin accordance with the processes disclosed herein. Such multi-layerproducts may find applicability in automotive, aerospace and armorapplications, among others.

In one embodiment, a multi-layer product is a AlLi-8xxx(HT) product,where the AlLi is a first layer of a Al—Li aluminum alloy productproduced according to the processes disclosed herein, and the 8xxx(HT)is a second layer of a heat treatable 8xxx aluminum alloy product, whichmay or may not be produced in accordance with the processes disclosedherein. Such multi-layer products may find applicability in packaging,automotive, aerospace and armor applications, among others.

In one embodiment, the second layer comprises an aluminum alloy havingimproved weldability (e.g., for spot welding) as compared to the firstaluminum alloy layer. This second layer may be any aluminum alloy, heattreatable or non-heat treatable, that has good weldability. Examples ofalloys having good weldability include 3xxx, 4xxx, 5xxx, 6xxx, and somelow-Cu 7xxx alloys. In one embodiment, the second layer has a lowermelting point than the first layer. Thus, during the welding of thefirst and second layers, the second layer may melt thereby creating abond between the first layer and the second layer (i.e., the weldingprocess results in creating an adhesive bond). In another embodiment,the second layer has a lower resistance than the first layer, which maybe useful in spot welding applications.

The multi-layer products may be produced in a variety of manners. In oneembodiment, the first and second layers are either (i) created togetheror (ii) coupled to one another prior to the cold working step (200). Thefirst and second layers may be created together during casting, such asvia the casting techniques described in U.S. Patent ApplicationPublication No. 20030079856 to Kilmer et al., U.S. Patent ApplicationNo. 20050011630 to Anderson et al., U.S. Patent Application No.20080182122 to Chu et al., and WO2007/098583 to Novelis (the so-calledFUSION™ casting process). The first and second layers may be coupledtogether (i.e., cast separately and then joined) via adhesive bonding,roll binding, and similar techniques. Since the first and second layersare adjacent one another prior to the cold working step, both layerswill receive at least 25% cold working due to the subsequent coldworking step (200). The multi-layer product may then be subsequentlythermally treated (300).

In one embodiment, when the second layer is a non-heat treatable alloy,the thermally treating step (300) may result in this second layer havinghigher ductility but lower strength as compared to the properties ofthat second layer in the as-cold worked condition. Conversely, since thefirst layer is a Al—Li aluminum alloy processed in accordance with theprocesses disclosed herein, the first layer may realize both improvedstrength and ductility as compared to the properties of the first layerin the as-cold worked condition. Thus the multi-layer product may havetailored lower strength, higher ductility properties on the outersurface of the multi-layer product, but with higher strength propertiestowards the inside of the multi-layer product. This may be useful, forexample, in armor applications, with the first layer resistingpenetration by a projectile and the second layer resisting spalling.

In another embodiment, the first and second layers are coupled to oneafter the cold working step (200) and prior to the thermally treatingstep. In this embodiment, each layer may receive a tailored amount ofpost-solutionizing cold work (if any for the second layer), but with thefirst layer receiving at least 25% cold working due to the cold workingstep (200). The multi-layer product may then be subsequently thermallytreated (300). In some embodiments, the thermally treating step (300)may be used to achieve the coupling of the two layers (e.g., as the asan adhesive bonding curing step; that is, a thermally treating step mayassist in adhesive bonding, which steps would be completed concomitantto one another in this embodiment).

In yet another embodiment, the first and second layers are coupled toone after the thermally treating step (300). In this embodiment, eachlayer may receive a tailored amount of cold work and a tailored amountof thermal treatment, but with the first layer receiving at least 25%cold working due to the cold working step (200), and the first layerbeing thermally treated to achieve at least one improved property (e.g.,a higher strength as compared to the as cold worked condition, or ascompared to a reference version of the product in the T6 temper).

The multi-layer products may include a third layer, or any number ofadditional layers. In one approach, a multi-layer product includes atleast three layers. In one embodiment, a layer of an Al—Li aluminumalloy product processed in accordance with the processes disclosedherein is “sandwiched” in between two outer layers. These two outerlayers may be the same alloy (e.g., both the same 1xxx alloy), or thesetwo outer layers may be different alloys (e.g., one a 1xxx aluminumalloy and the other another type of 1xxx alloy; as another example, onea 1xxx alloy, the other a 5xxx alloy, so on and so forth).

In one approach, the multi-layer product is a NHT-AlLi-NHT product,where NHT stands for a layer of non-heat treatable alloy, as describedabove, and the AlLi is a layer of AlLi aluminum alloy product producedaccording to the processes disclosed herein. In one embodiment, themulti-layer product is a 3xxx-AlLi-3xxx product, with the outer layersbeing 3xxx aluminum alloy product and with the inner layer being a Al—Lialuminum alloy product processed according to the processes disclosedherein. Such multi-layer products may find utility in automotiveapplications (e.g., panels or body-in-white), aerospace applications(e.g., fuselage skin, stringers, frames, bulkheads, spars, ribs, and thelike), and marine structural applications (e.g., bulkheads, frames,hulls, decks, and the like), to name a few). Similarly, 5xxx-AlLi-5xxxproducts could be used for the same or similar purposes. Othercombinations of NHT-AlLi-NHT may be employed, and it is not requiredthat the same NHT be used on both sides of the Al—Li layer, i.e.,different NHT alloys may be used to sandwich the Al—Li layer.

In another approach, the multi-layer product is a AlLi(1)-HT-AlLi(2)product, where HT stands for a layer of heat treatable alloy, asdescribed above, and where at least one of the AlLi(1) and AlLi(2) is alayer of Al—Li aluminum alloy product produced according to the newprocesses disclosed herein, which layers may have the same compositionor different compositions. In one embodiment, both AlLi(1) and AlLi(2)layers have the same composition and are produced according to the newprocesses disclosed herein. The AlLi(1)-HT-AlLi(2) Such products may beuseful in automotive applications in closure panels, body-in-white (BIW)structure, seating systems or suspension components, among others. Suchproducts might also be useful in commercial or military aerospacecomponents, including launch vehicle or payload components. Suchcomponents might further be useful for commercial transportationproducts in light, medium or heavy duty truck structure or buses. TheAlLi-HT-AlLi products could be useful in multi-piece wheels for autos,trucks or buses. Such products could also be useful for building panels.Such products could further be useful for armor components.

In another approach, the multi-layer product is a AlLi-NHT-AlLi product,where NHT stands for a layer of a non-heat treatable alloy, as describedabove, and the AlLi is a layer of a Al—Li aluminum alloy productproduced according to the processes disclosed herein. Such products maybe useful in components used in marine applications for ships or boatsand amphibious military vehicles. Such products might also be useful forautomotive applications in closure panels, BIW structure, seatingsystems or suspension components, among others. Such products mightfurther be useful for packaging systems (e.g., containers (cans,bottles, closures), trays). The AlLi-NHT-AlLi products might also beuseful for lighting components. In particular, if the Al—Li alloy iscombined with a HT alloy of lower strength, this could be useful inautomotive crashworthy or energy-absorbing applications.

In another approach, the multi-layer product is a HT(1)-AlLi-HT(2)product, where HT stands for layers of a heat treatable alloy, asdescribed above, which layers (HT(1) and HT(2)) may have the same ordifferent compositions, and where the AlLi is a layer of a Al—Lialuminum alloy product produced according to the processes disclosedherein. Such products may be useful in commercial or military aerospacecomponents, including launch vehicle or payload components. Inparticular, if the Al—Li alloy is combined with a HT alloy of higherstrength, this could be useful in automotive crashworthy orenergy-absorbing applications

In another approach, the multi-layer product is a HT-AlLi-NHT product,where HT stands for a layer of heat treatable alloy, as described above,AlLi is a layer of Al—Li aluminum alloy product produced according tothe processes disclosed herein, and NHT stands for a layer of a non-heattreatable alloy, as described above. Such products may be useful incommercial or military aerospace components, including launch vehicle orpayload components. Such products might also be useful for automotiveapplications in closure panels, BIW structure, seating systems orsuspension components. Such products could be useful in automotivecrashworthy or other energy-absorbing applications. Such componentsmight further be useful for commercial transportation products in light,medium or heavy duty truck structure or buses. Such products couldfurther be useful for armor components.

In another approach, the multi-layer product is a AlLi-NHT-HT product,where the AlLi is a layer of Al—Li aluminum alloy product producedaccording to the processes disclosed herein, the NHT stands for a layerof a non-heat treatable alloy, as described above, and HT stands for alayer of heat treatable alloy, as described above. Such products may beuseful in commercial or military aerospace components, including launchvehicle or payload components. Such products might also be useful forautomotive applications in closure panels, BIW structure, seatingsystems or suspension components. Such components might further beuseful for commercial transportation products in light, medium or heavyduty truck structure or buses. Such products could be useful inautomotive crashworthy or other energy-absorbing applications.

In another approach, the multi-layer product is a AlLi-HT-NHT product,where the AlLi is a layer of Al—Li aluminum alloy product producedaccording to the processes disclosed herein, the HT stands for a layerof heat treatable alloy, as described above, and NHT stands for a layerof a non-heat treatable alloy, as described above. Such products may beuseful in components used in marine applications for ships or boats andamphibious military vehicles. Such products might also be useful forautomotive applications in closure panels, BIW structure, seatingsystems or suspension components. Such products might further be usefulfor packaging systems (e.g., containers (cans, bottles, closures),trays). Such products could also be useful for building panels. Suchproducts could further be useful for armor components. The AlLi-HT-NHTproducts might also be useful for lighting components.

In one approach, a method comprises casting an aluminum alloy body,wherein, after the casting, the aluminum alloy body comprises a firstlayer of a first heat treatable alloy, and a second layer of either asecond heat treatable alloy or a non-heat treatable alloy (e.g., usingthe techniques described in commonly-owned U.S. Patent Publication No.US 2010/0247954 to Chu et al., which patent application is incorporatedherein by reference in its entirety), (b) solutionizing the aluminumalloy body, (c) cold working the aluminum alloy body, wherein the coldworking induces at least 25% cold work in the aluminum alloy body, and(d) thermally treating the aluminum alloy body. Thus, an aluminum alloybody having a first layer and a second layer may be produced, and whichlayers may be distinct from one another. In one embodiment, the secondlayer comprises a second heat treatable alloy. In one embodiment, thesecond heat treatable alloy is different than the first heat treatablealloy. In another embodiment, the second heat treatable alloy is thesame as the first heat treatable alloy (but are distinct layers). Thisaluminum alloy body may realize improved strength, ductility, or otherproperties, such as any of the properties described in the Propertiessection (Section H), above. In one embodiment, the method comprises,after the thermally treating step, assembling an assembly having thisaluminum alloy body having the at least first and second layers. In oneembodiment, this aluminum alloy body having the at least first andsecond layers is an armor component. In another embodiment, thisaluminum alloy body having the at least first and second layers is anautomotive component.

In another embodiment, a method comprises casting an aluminum alloybody, wherein, after the casting, the aluminum alloy body comprises acomposition gradient, wherein a first region comprises a firstcomposition, and a second region comprises a second composition, thesecond composition being more than just nominally different than thefirst composition (e.g., a compositional gradient beyond meremacrosegregation effects). Techniques available to produce such aluminumalloy bodies are described in commonly-owned U.S. Patent Publication No.2010/0297467 to Sawtell et al., which patent application is incorporatedherein by reference in its entirety. In one embodiment, the firstcomposition is a composition that makes it a heat treatable aluminumalloy (i.e., capable of precipitation hardening), and the second regionof the body has more than a nominally different composition than theheat treatable alloy of the first region. In one embodiment, acontinuous concentration gradient exists between the first and secondregions. The continuous concentration between the first and secondregions gradient may be linear, or may be exponential. In oneembodiment, the aluminum alloy body comprises a third region. In oneembodiment, the third region comprises the same concentration as thefirst region but is separated from the first region by the secondregion. In one embodiment, the concentration gradient between the firstand second regions is linear. In some of these embodiments, theconcentration gradient between the second and third regions is linear.In some of the embodiments, the concentration gradient between thesecond and third regions is exponential. In one embodiment, the aluminumalloy body having the purposeful composition gradient may besolutionized, and then cold worked, wherein the cold working induces atleast 25% cold work in the aluminum alloy body, and then thermallytreated. Thus, an aluminum alloy body having a tailored compositiongradient may be produced. This aluminum alloy body may realize improvedstrength, ductility, or other properties, such as any of the propertiesdescribed in the Properties section (Section H), above. In oneembodiment, the method comprises, after the thermally treating step,assembling an assembly having this aluminum alloy body having the firstregion and the second region. In one embodiment, this aluminum alloybody having the at least first and second regions is an armor component.In another embodiment, this aluminum alloy body having at the first andsecond regions is an automotive component. In another embodiment thisaluminum alloy body having at the first and second regions is anaerospace component.

As mentioned above, any number of additional aluminum alloy layers maybe used in any of the above-described multi-layer approaches and/orembodiments. Furthermore, any number of non-aluminum alloy layers (e.g.,plastic layers, resins/fiber layers) may be added to any of theabove-described multi-layer approaches and/or embodiments. Furthermore,any of the above-described multi-layer products may be employed with thecold work gradient processing techniques described in the Cold Worksection (Section B(iii)), above.

Examples of multi-layer product styles that may be employed withproducts made by the new processes disclosed herein include thosedescribed in, for example, U.S. Patent Application Publication Nos.2008/0182122 to Chu et al., 2010/0247954 to Chu et al., 2010/0279143 toKamat et al., 2011/0100579 to Chu et al., and 2011/0252956 to Rioja etal.

J. Combinations

The preparing, cold working, thermally treating, and optional finaltreatment apparatus and methodologies described above in Sections A, B,C, and F, respectively, may be combined in any suitable manner asdescribed herein to achieve any of the improved aluminum alloy bodiesand/or properties described in Sections D and H, any of themicrostructures described in Section E, and to achieve any of thealuminum alloy bodies and products described in any of Sections A-I, andthe compositions provided for in Section G may be tailored, asappropriate to achieve such aluminum alloy bodies. Thus, all suchcombinations of the methodologies and apparatus described in theseSections A-I are recognized as being combinable for such purposes, andtherefore can be combined and claimed in any suitable combination toprotect such inventive combinations. Furthermore, these and otheraspects, advantages, and novel features of this new technology are setforth in part in the description that follows and will become apparentto those skilled in the art upon examination of the description andfigures, or may be learned by practicing one or more embodiments of thetechnology provided for by the patent application.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flow chart illustrating a conventional process for producingaluminum alloy products.

FIG. 2 a is a flow chart illustrating a new process for producingaluminum alloy products.

FIGS. 2 b-2 c are schematic views of example aluminum alloy bodies thatmay be cold worked to produce differential cold work zones or gradients.

FIGS. 2 d-2 f illustrate various manners of cold working the aluminumalloy bodies of FIGS. 2 b-2 c to produce cold worked aluminum alloybodies having tailored cold worked zones, as well as the produced bodiesthemselves.

FIGS. 2 g-2 i illustrate other examples of aluminum alloy bodies thatmay be cold worked to produce differential cold work zones or gradients,one example of cold working such bodies, and the produced bodiesthemselves.

FIGS. 2 j-2 l illustrate various manners of producing cold rolledproducts having differential cold work zones or gradients.

FIG. 2 m is a top-down view of the rolled aluminum alloy productproduced via the process of FIG. 2 j.

FIGS. 2 n-2 o illustrate various types of automotive components that maybe produced in accordance with the new methods described herein.

FIGS. 2 p-1 to 2 p-3 are exploded views of an automotive vehicle,illustrating various types of automotive components that may be producedin accordance with the new methods described herein.

FIGS. 2 q-1 to 2 q-9 are flow charts illustrating various examplemethods for producing improved aluminum alloy bodies.

FIG. 2 r illustrates various schematic views of various aluminum alloyammunition cartridges, in intermediate and final forms.

FIGS. 2 s-1 to 2 s-5 are flow charts illustrating various examplemethods for producing improved aluminum alloy containers.

FIG. 2 s-6 is a schematic side view illustrating one embodiment of analuminum alloy container that may be produced in accordance with the newmethods described herein.

FIG. 2 s-7 is a schematic side view illustrating one embodiment of analuminum alloy closure that may be produced in accordance with the newmethods described herein.

FIGS. 2 t-1 to 2 t-2 are schematic views illustrating one perspectiveview and a cross-sectional view, respectively, of an aluminum alloywheel that may be produced in accordance with the new methods describedherein.

FIGS. 3-5 are flow charts illustrating various embodiments of preparingan aluminum alloy body for post-solutionizing cold work.

FIG. 6 a is a flow chart illustrating one embodiment of preparing analuminum alloy body for post-solutionizing cold work, where thesolutionizing step is completed concomitant to a placing step (e.g.,concomitant to a continuous casting step).

FIGS. 6 b-1 and 6 b-2 are schematic views illustrating one embodiment ofa continuous casting apparatus for preparing aluminum alloy bodies forpost-solutionizing cold work in accordance with FIG. 6 a.

FIGS. 6 c-6 f and 6 l-6 k are graphs illustrating data associated withaluminum alloy bodies produced in accordance with the continuous castingapparatus of FIGS. 6 b-1 and 6 b-2.

FIGS. 6 g-6 j and 6 m are micrographs of aluminum alloy bodies producedin accordance with the continuous casting apparatus of FIGS. 6 b-1 and 6b-2.

FIGS. 6 n and 6 o are schematic views illustrating an optional stripsupport mechanism that may be employed with the continuous castingapparatus of FIGS. 6 b-1 and 6 b-2.

FIG. 6 p is a flow chart illustrating one embodiment of completing aconcomitant casting and solutionizing step to produce an aluminum alloybody having particulate matter therein.

FIG. 6 q is a schematic view illustrating one embodiment of a continuouscasting apparatus for preparing aluminum alloy bodies forpost-solutionizing cold work in accordance with FIGS. 6 a and 6 p, wheresuch aluminum alloy bodies contain particulate matter therein.

FIGS. 6 r-6 s are micrographs of aluminum alloy bodies produced inaccordance with the continuous casting apparatus of FIG. 6 q havingparticulate matter therein.

FIG. 6 t is a flow chart illustrating one embodiment of completing aconcomitant casting and solutionizing step to produce an aluminum alloybody having immiscible metal therein.

FIGS. 6 u-6 w are schematic views illustrating one embodiment of acontinuous casting apparatus for preparing aluminum alloy bodies forpost-solutionizing cold work in accordance with FIGS. 6 a and 6 t, wheresuch aluminum alloy bodies contain immiscible metal therein.

FIG. 6 x is a micrograph of an aluminum alloy body produced inaccordance with the continuous casting apparatus of FIGS. 6 u-w havingimmiscible metal therein.

FIGS. 7-8 are flow charts illustrating embodiments of preparing analuminum alloy body for post-solutionizing cold work.

FIG. 9 is a flow chart illustrating one embodiment of a method forproducing a rolled aluminum alloy body.

FIG. 10 is a graph illustrating R-values as a function of orientationangle for various aluminum alloy bodies.

FIGS. 11 a-11 e are optical micrographs illustrating aluminum alloy bodymicrostructures; the optical micrographs were obtained by anodizing thesamples and viewing them in polarized light.

FIG. 12 is a flow chart illustrating one method of producingmulti-layered aluminum alloy products.

FIG. 13 is a schematic view illustrating the L, LT and ST directions ofa rolled product.

FIGS. 14-16 are graphs illustrating the thermal treatment response ofvarious Al—Li alloy bodies.

FIGS. 17-20 are graphs illustrating the strength-toughness performanceof various Al—Li alloy bodies.

FIGS. 21-29 are graphs illustrating various properties of 2199 Al—Lialloy bodies, both conventionally processed and as processed inaccordance with the new processes described herein.

DETAILED DESCRIPTION Example 1 Testing of 2xxx Al—Li Alloy with NewProcess

A 2xxx Al—Li alloy having the composition listed in Table 5 is cast,homogenized, and hot rolled into plate/sheet having intermediate gaugesof about 0.53 inch, 0.32 inch, 0.16 inch (×2), and 0.106 inch,respectively. One of the 0.16 inch samples (the control) is then coldrolled to a final gauge of about 0.08 inch, solution heat treated bysoaking at about 940° F. for about 120 minutes, followed by a cold waterquench. The control sample is then stretched 1-2%.

TABLE 5 Composition of 2xxx Al—Li alloy (all values in weight percent)Other Others Si Fe Cu Mg Zn Zr Li Ag Mn Each Total Bal. 0.02 0.02 3.720.81 0.35 0.08 0.76 0.36 0.31 ≦0.05 ≦0.15 AlThe other samples are first solution heat treated (by the same process)and then cold rolled to a final gauge of 0.08 inch, representing about85%, 75%, 50%, and 25% cold work, respectively. All samples arenaturally aged for about four days, and then thermally treated at threetemperatures (250° F., 290° F., and 330° F.) for various times.Mechanical and electrical conductivity tests are then conducted, theresults of which are provided in Tables 6-8 for each thermal treatmenttemperature.

TABLE 6 Strength of 2xxx Al—Li alloy at various thermal treatment times(250° F.) Sheet B Sheet C Sheet D Sheet E Sheet A (new) (new) (new)(new) (T6) 85% CW 75% CW 50% CW 25% CW (ksi) (ksi) (ksi) (ksi) (ksi)Time (hr) TYS UTS TYS UTS TYS UTS TYS UTS TYS UTS 0 39.6 59.4 77.1 85.771.6 82.4 60.9 73.3 55.1 67.5 0.5 34.9 55.6 74.4 85.3 68.6 82 57.8 72.652.6 67.9 12 34.2 55 77.6 89.1 71.6 85 60.3 75.6 54.5 70.5 24 33.6 5579.4 89.2 73.8 86 62.5 77 55.7 71.3 48 33.9 54.8 83.9 91.4 78.7 87.165.6 78.3 58.7 72.1 72 34.7 55.3 86.8 91.9 81.3 89.3 69.3 79.6 62.9 74.2

TABLE 7 Strength of 2xxx Al—Li alloy at various thermal treatment times(290° F.) Sheet B Sheet C Sheet D Sheet E Sheet A (new) (new) (new)(new) (T6) 85% CW 75% CW 50% CW 25% CW (ksi) (ksi) (ksi) (ksi) (ksi)Time (hr) TYS UTS TYS UTS TYS UTS TYS UTS TYS UTS 0 39.6 59.4 77.1 85.771.6 82.4 60.9 73.3 55.1 67.5 0.5 32.7 53.9 74.7 87.3 68.7 82.5 58 73.252.4 68.4 4 32.6 53.8 79.4 88.4 73.1 85.4 61.7 75.9 54.9 70.4 8 32.653.7 83.6 90.5 77.1 85.9 66.1 77.6 57.9 71.3 24 34.8 55.5 91.4 93.4 86.791 76.8 83.5 70.5 78.3 48 46.6 62.1 92.9 95.3 89.8 92.5 81.7 87.1 78.484

TABLE 8 Strength of 2xxx Al—Li alloy at various thermal treatment times(330° F.) Sheet B Sheet C Sheet D Sheet E Sheet A (new) (new) (new)(new) (T6) 85% CW 75% CW 50% CW 25% CW (ksi) (ksi) (ksi) (ksi) (ksi)Time (hr) TYS UTS TYS UTS TYS UTS TYS UTS TYS UTS 0 39.6 59.4 77.1 85.771.6 82.4 60.9 73.3 55.1 67.5 0.5 32.2 51.8 77.2 86.8 71.2 83.3 59.574.4 53.1 68 2 32.4 52.7 86.4 90.2 80.7 87.3 68.4 77.8 60.2 72.1 4 33.453.5 90.7 92.8 86.9 90.2 76 82.6 70.7 78.1 8 47.3 62.7 90.9 93.6 88.791.8 81.6 85.8 77.5 83.5 12 58.5 70.1 91.1 93.8 88.8 91.8 81.9 86.3 79.184.2

As illustrated in Tables 6-8, above, and FIGS. 14-16, Sheets B through Emade by the new process realize an increase in strength. Indeed, Sheet Bwith 85% CW and thermally treated at 330° F. with 85% CW realizes astrength of 90.7 ksi (within 1 ksi of peak) after only 4 hours ofthermal treatment. The conventionally processed alloy (Sheet A) in theT6 temper does not appear to have reached its peak strength even after12 hours of thermal treatment, and then only realizes a strength ofabout 58.5 ksi. In other words, Sheet B achieves about a 55% increase intensile yield strength over the strength of 58.5 ksi for the Sheet Amaterial, and with only 4 hours of thermal treatment (i.e., 66.7%faster; (1-4/12)*100%=66.7%). Stated differently, new Sheet B achievesabout a 55% increase in strength over Sheet A and in about ⅓^(rd) of thetime required for Sheet A to achieve its highest measured strength.

Given these strength increases, a significant drop in ductility would beexpected. However, as shown in Table 9, below, the 2xxx Al—Li alloybodies achieve good elongation values. All elongation values are inpercent. Similar elongation values are measured for the samplesthermally treated at 290° F. and 330° F.

TABLE 9 Elongation (%) of 2xxx Al—Li alloy at various thermal treatmenttimes (250° F.) Sheet B Sheet C Sheet D Sheet E Time Sheet A (new) (new)(new) (new) (hr) (T6) 85% CW 75% CW 50% CW 25% CW 0 24 8 8 10 10 0.5 2411 11 12 12 12 24 15 14 17 16 24 26 14 15 17 16 48 26 14 15 16 16 72 2614 16 12 14The measured electrical conductivity values at 250° F. are provided inTable 10, below. All electrical conductivity values are in percent IACS(International Annealed Copper Standard). Similar electricalconductivity values are measured for the samples thermally treated at290° F. and 330° F.

TABLE 10 Elec. Cond. of 2xxx Al—Li alloy at various thermal treatmenttimes (250° F.) Sheet B Sheet C Sheet D Sheet E Time Sheet A (new) (new)(new) (new) (hr) (T6) 85% CW 75% CW 50% CW 25% CW 0 23.9 22.4 22.6 2323.5 0.5 24 22.5 22.5 23.1 23.5 12 24.1 22.3 22.4 22.9 23.4 24 24.2 22.322.5 23.1 23.4 48 24.1 22.5 22.6 23.3 23.6 72 24.3 22.6 22.9 23.3 23.7The results of Example 1 illustrate that the cold working and thermaltreatment steps must be appropriately accomplished to achieve improvedproperties (e.g., strength). As shown in FIGS. 14-16, alloys that arethermally treated for an insufficient period of time may not realize theimproved properties, as illustrated by the reduction in strength ascompared to the as-cold worked condition. Alloys that are thermallytreated for an excessive period may also not realize the improvedproperties.

Additional mechanical properties of this 2xxx Al—Li alloy are tested.Specifically, the longitudinal (L) and long transverse (LT) strength,elongation, and fracture toughness properties of the 2xxx Al—Li alloybodies were tested, the results of which are provided in Tables 11-12below. These results indicate that similar strength and elongationproperties may be realized by 2xxx Al—Li alloy bodies in the L and LTdirections.

TABLE 11 Strength and Elongation Properties of the 2xxx Al—Li alloyThermal Thermal Cold treatment treatment TYS (L) UTS (L) Elong. (L) workTemp (F.) Time (hr) (ksi) (ksi) (%) Control 330 36 65 72.4 8 85% N/A 080.1 82.9 3 85% 290 8 83 89.1 10 85% 290 24 88.1 91.6 7 75% N/A 0 7579.2 4 75% 290 8 78.9 86.7 10 75% 290 24 85 89.1 7 Thermal Thermal Coldtreatment treatment TYS-LT UTS-LT Elong. (LT) work Temp (F.) Time (hr)(ksi) (ksi) (%) Control 330 36 65.2 73.5 7 85% N/A 0 76 86.5 8 85% 290 882.2 89.6 12 85% 290 24 90.6 94.1 10 75% N/A 0 70.9 82.7 9.5 75% 290 876.8 85.7 13 75% 290 24 86.8 91 10

TABLE 12 Toughness Properties of the 2xxx Al—Li alloy Treatment ColdTemperature Treatment K_(Q) (L-T) K_(R25) (L-T) work (F.) Time (hr)(ksi√in) (ksi√in) Control 330 36 35.6 65.7 85% N/A 0 34.6 40.8 85% 290 839.0 65.8 85% 290 24 34.9 66.9 75% N/A 0 38.7 41.6 75% 290 8 38.7 71.675% 290 24 56.9 67.3 Treatment Cold Temperature Treatment T-L K_(Q) work(F.) Time (hr) (ksi√in) K_(R25), T-L Control 330 36 31.7 72.2 85% N/A 035.9 49.3 85% 290 8 40.1 90.9 85% 290 24 41.5 76.9 75% N/A 0 41.8 52.875% 290 8 43.8 77.7 75% 290 24 52.1 97.5

The fracture toughness tests were conducted in accordance with ASTM teststandards ASTM E561 and ASTM B646 (for K_(app) and K_(R25)), and E399and B645 (K_(IC)/K_(Q)). The toughness test specimens were: a middlecrack fracture specimen (M(T)) was used for the K_(app) measurement. Thespecimen width (W) was 6.3 inches, thickness (B) was 0.08 inch and theinitial crack length (2a₀) was 1.573 inches, i.e. 2 a₀/W=0.25. A compacttension fracture specimen (C(T)) was used for K_(R25) and K_(Q)measurements. The specimen width (W) was 2.5 inches and thickness (B)was 0.07 inch, with a nominal initial crack length (a₀) of 1.25 and(a₀)/W=0.50.

Those skilled in the art will appreciate that the numerical values ofK_(Q), K_(app) and K_(R25) typically increase as the test specimen widthincreases. K_(Q), K_(app) and K_(R25) are also influenced by specimenthickness, initial crack length and test coupon geometry. Thus, K_(Q),K_(app) and K_(R25) values usually can be reliably compared only fromtest specimens of equivalent geometry, width, thickness and initialcrack length.

The 2xxx Al—Li alloy body realizes good toughness. Despite thesignificant increase in strength over the control, the new 2xxx Al—Lialloy bodies realize improved toughness over the control alloys. This isillustrated in FIGS. 17-20. For example, the 75% CW sheet realizes a21.4-30.8% improvement in tensile yield strength (L) and with acorresponding 9-60% improvement in plane-strain toughness (K_(Q) L-T)and a 2-9% improvement in plane-stress toughness (K_(R25) L-T) over thecontrol sheet. The 75% CW sheet also realizes a 17.8-33.1% improvementin tensile yield strength (LT) and with a corresponding 38-64%improvement in plane-strain toughness (K_(Q) T-L) and a 7-35%improvement in plane-stress toughness (K_(R25) T-L) over the controlsheet. These combinations of strength and toughness are also realizedwith good ductility, with the new aluminum alloy bodies all realizing anelongation of 10-13%.

The 2xxx Al—Li alloy bodies are also tested for grain structure as perthe OIM procedure, described above. The results are provided in Table13, below.

TABLE 13 Microstructure (OIM) Properties of the 2xxx Al—Li alloyMeasurement First Type Grains Percent Sample Location per OIM (vol.fraction) Unrecrystallized Control T/4 to surface 0.85 15% 25% CW T/4 tosurface 0.33 67% 50% CW T/4 to surface 0.21 79% 75% CW T/4 to surface0.14 86% 85% CW T/4 to surface 0.07 93%

The new 2xxx Al—Li alloy bodies have a predominately unrecrystallizedmicrostructure, having a volume fraction of not greater than 0.33 firsttype grains (i.e., 67% unrecrystallized) in all instances. Conversely,the control body is nearly fully recrystallized having a volume fractionof 0.85 first type grains (i.e., 15% unrecrystallized).

The R-values of the 2xxx Al—Li alloy bodies are also tested as per theR-value generation procedure, described above. The results areillustrated in FIG. 10, described above. The new 2xxx Al—Li alloy bodieshave high normalized R-values, achieving a peak (maximum) normalizedR-value at an orientation angle of 45-55°. These high R-values areindicative of the unique texture, and thus microstructure, of the newAl—Li alloy bodies as well as the new Al—Li alloy bodies describedherein. The new 2xxx Al—Li alloy bodies realize about 590% to 1030%higher maximum R-values as compared to the R-value of the control body(for the purpose of measuring R-values, the control is in the T4 temper,not the T6 temper).

Example 2 Testing of Second 2xxx+Li Alloy

A 2xxx+Li alloy commonly known as 2199, and having the compositionlisted in Table 14, below, is prepared similar to that of Example 1,except that the final thickness of the sheet is about 0.125 inch.

TABLE 14 Composition of Al—Li alloy 2199 (all values in weight percent)Other Others Si Fe Cu Mg Zn Zr Li Mn Ti Each Total Bal. 0.02 0.02 2.570.11 0.59 0.08 1.57 0.28 0.03 ≦0.05 ≦0.15 Al

The properties of these 2199 aluminum alloy bodies as thermally treatedat 290° F., 310° F., and 330° F. are provided in FIGS. 21-29. Like thefirst Al—Li alloy of Example 1, the 2199 Al—Li alloys with high coldwork achieve improved strength and in shorter thermal treatment times ascompared to the control 2199 alloy in the T6 temper. Good ductility isalso achieved. These results show that other Al—Li alloys may realizesimilar improvements in strength and other properties. Thus, the newmethods described herein may be applicable to various 2xxx+Li, 5xxx+Li,and 7xxx+Li aluminum alloys, as well as aluminum alloys containinglithium as the predominate alloying ingredient other than aluminum.

Example 2 Surface Roughness of 2xxx+Li Alloy

The surface roughness of a 2199 was tested. Specifically, a 2199 ingotwas hot rolled to intermediate gauge, and then split into a first setand a second set. The first set was processed in accordance withconventional practices, i.e., cold rolled to final gauge and thensolutionized. Some of the first set are then stretched a small amountfor flatness (about 2%), and then thermally treated (“the 1S-A pieces”).Others of the first set are stretched a small amount for flatness (about2%) and then naturally aged to a substantially stable condition (“the1S-B pieces”). The second set of materials were processed according tothe new processes disclosed herein, i.e., solutionized, then cold rolledto final gauge, either about 50% or about 75% (the “2S-50” and “2S-75”pieces, respectively). Some of the 2S-50 pieces are naturally aged (the“2S-50-NA pieces”) and some of the 2S-50 pieces are thermally treated(the “25-50-TT pieces”). Likewise, some of the 2S-75 pieces arenaturally aged (the “2S-75-NA pieces”) and some of the 2S-75 pieces arethermally treated (the “25-75-TT pieces”).

The surface roughness (Ra) of the various pieces were tested, bothbefore and after stretching and in the L and LT directions. The surfaceroughness was measured using a MicroXAM surface microscope (KLA Tencor,ADE Division, Milpitas, Calif., USA). A 10× image was used with a fieldof view of 0.74 mm×0.74 mm for the measurement. Five random fields wereselected and the average roughness (Ra)—average height of the bumps on asurface—was obtained. The result are provided in Table 15, below.

TABLE 15 Surface Roughness of Al—Li alloy 2199 Stretch Ra Ra 2199 Alloyorientation (before stretch) (after stretch) 1S-B L 32 105 1S-B LT 31129 1S-A L 30 75 1S-A LT 29 99 2S-50-NA L 29 29 2S-50-NA LT 24 352S-50-TT L 25 34 2S-50-TT LT 26 40 2S-75-NA L 21 21 2S-75-NA LT 15 192S-75-TT L 21 22 2S-75-TT LT 17 26

The sheets processed in accordance with the new methods described hereinrealize improved surface roughness properties after stretching than theconventionally processed materials. Indeed, all of the conventionallyprocessed materials, after stretching, realized a surface roughness ofat least 75 in the L direction and at least 99 in the LT direction, withthe non-thermally treated materials (1S-B) realizing the worstproperties. Conversely, the new invention materials realized low surfaceroughness values with all surface roughness measurements being notgreater than 40. Furthermore, some of the new materials realized evenlower surface roughness prior to stretching even though they weresignificantly cold rolled after solutionizing. Thus, Al—Li products madein accordance with the new processes disclosed herein may realizeimprove surface roughness properties (e.g., low or no Ludering; low orno orange peel, among others).

While various specific embodiments of new processes for preparingaluminum alloy bodies having improved properties are described indetail, it should be recognized that the features described with respectto each embodiment may be combined, in any combination, with featuresdescribed in any other embodiment, to the extent that the features arecompatible. For example, any of the aluminum alloy bodies, predeterminedshaped products, components and assemblies described herein, andcorresponding processes techniques for making the same may be combined,in any appropriate combination, and they and their associated improvedproperties may be appropriately claimed in this or a continuing patentapplication or a divisional patent application, as appropriate. Also,additional apparatus and/or process steps may be incorporated to theextent they do not substantially interfere with operation of the newprocesses disclosed herein. Other modifications will become apparent tothose skilled in the art. All such modifications are intended to bewithin the scope of the present invention. Furthermore, it is apparentthat modifications and adaptations of those embodiments will occur tothose skilled in the art. However, it is to be expressly understood thatsuch modifications and adaptations are within the spirit and scope ofthe present disclosure.

What is claimed is:
 1. A method comprising: (a) preparing an aluminumalloy strip for post-solutionizing cold work, (i) wherein the aluminumalloy strip includes 0.25-5.0 wt. % lithium, (ii) wherein the preparingstep comprises continuously casting the aluminum alloy sheet, thecontinuously casting step comprising: (A) delivering molten aluminummetal comprising the 0.25-5.0 wt. % lithium to a pair of spaced apartrotating casting rolls defining a nip therebetween; (B) advancing themetal between surfaces of the casting device rolls, wherein the advancecomprises: (I) first forming two solid outer regions adjacent surfacesof the casting device rolls; (II) second forming a semi-solid innerregion containing dendrites of the metal; (III) wherein the inner regionis located between the two outer concentration regions; (IV) wherein thefirst forming and second forming steps are completed concomitant to oneanother; (V) breaking the dendrites in the inner region at or before thenip; and (C) solidifying the semi-solid inner region to produce thealuminum alloy body comprised of the inner region and the outer regions;(iii) wherein the preparing step comprises solutionizing of the aluminumalloy strip; (b) after the preparing step (a), cold working the aluminumalloy sheet by at least 25%; and (c) after the cold working step (b),thermally treating the aluminum alloy sheet; wherein the cold workingand the thermally treating steps are accomplished to achieve an increasein long-transverse tensile yield strength as compared to areference-version of the aluminum alloy body in the as cold-workedcondition.
 2. The method of claim 1, wherein the solutionizing stepcomprises solution heat treating and quenching, wherein the solutionheat treating is accomplished due to the continuous casting, and whereinthe preparing comprises: removing the aluminum alloy strip from acontinuous casting apparatus; and after the removing step, and beforethe aluminum alloy strip reaches a temperature of 700° F., quenching thealuminum alloy strip, wherein the quenching reduces the temperature ofthe aluminum alloy strip at a rate of at least 100° F. per second,thereby accomplishing the solutionizing; wherein the temperature of thealuminum alloy strip exiting the continuous casting apparatus is higherthan the temperature of the aluminum alloy strip during the quenchingstep.
 3. The method of claim 2, wherein the quenching comprises coolingthe aluminum alloy strip to a temperature of not greater than 150° F. 4.The method of claim 3, wherein the quenching is accomplished by aquenching apparatus downstream of the continuous casting apparatus. 5.The method of claim 1, wherein the cold working comprises cold workingthe aluminum alloy strip by at least 50%.
 6. The method of claim 1,wherein the thermally treating comprises heating the aluminum alloystrip to within 5 ksi of peak strength.
 7. The method of claim 1,wherein the preparing and cold working steps are accomplishedcontinuously and in-line.
 8. A method comprising: (a) receiving analuminum alloy body, wherein the aluminum alloy body comprises 0.25-5.0wt. % lithium, wherein the aluminum alloy body was prepared bysolutionizing, and then cold working, wherein the cold working inducedat least 25% cold work in the aluminum alloy body, and then firstthermally treating to achieve a first predetermined selected condition;(b) second thermally treating the aluminum alloy body; (i) wherein thesecond thermally treating step is accomplished to achieve a secondpredetermined selected condition, and such that the aluminum alloy bodyrealizes a higher tensile yield strength over a reference version of thealuminum alloy body in the T6 temper.
 9. The method of claim 8,comprising: forming the aluminum alloy body into a predetermined shapedproduct.
 10. The method of claim 9, wherein the forming occurs duringthe second thermally treating step.
 11. The method of claim 8, whereinthe first predetermined selected condition is a predetermined firststrength and the second predetermined selected condition is apredetermined second strength.
 12. The method of claim 11, wherein thepredetermined second strength is higher than the predetermined firststrength.
 13. A method comprising: (a) receiving a solutionized heattreatable aluminum alloy body, wherein the aluminum alloy body comprises0.25-5.0 wt. % lithium, wherein the aluminum alloy body was prepared bysolutionizing and then cold working, wherein the cold working induced atleast 25% cold work in the aluminum alloy body; and (b) forming thealuminum alloy body into a predetermined shaped product, wherein, duringthe forming step, the aluminum alloy body is subjected to a temperaturein the range of from at least 150° F. to below the recrystallizationtemperature of the aluminum alloy body.
 14. The method of claim 13,wherein the cold working comprises cold rolling the aluminum alloy bodyto final gauge.
 15. The method of claim 14, wherein the predeterminedshaped product is a component of a vehicle.